The yeast and worms, simple biological evolution is how to birds and mammals such complex biological? A study conducted comparative genomics research shows, widely the answer to the problem may be hidden in the biological waste deoxyribonucleic acid (DNA). The scientists found that the more complex biological and its carrying the junk DNA, and the more they didn't code "useless" DNA help higher evolution of the complex.
Since the first eukaryotes -- including from yeast to human nuclei creatures -- since to be interpreted genome, scientists have wanted to know why, most of the DNA and no biological form useful genes. From the chromosome mutation protection to support structure for the so-called junk DNA could explain a lot of. But last year from humans, mice and rats of identical about junk DNA results show that in this area are important may include the regulating mechanism, which can control the basic biological chemical reactions and development process, this will help evolution of a more complicated. Compared with simple eukaryotes, complex organisms have more genes mutating will undoubtedly the greatly strengthened the fact that this one.
In order to this problem by a deeper understanding of the university of California, Santa cruz, UCSC (David) calculation biologists Haussler research group, a leading to 5 kinds of vertebrates -- people, rats, mice, chicken and the junk DNA sequences blowfish, with four insects, two worms and seven kinds of yeast junk DNA sequences are compared. Researchers from the result of an astonishing mode: the more complex and more important to junk DNA.
The possibility of implicit in different kinds of creatures, if you have the same DNA, so these will DNA is used to solve some key problems. The yeast and vertebrate sharing a certain amount of DNA, after all, they all need to manufacture protein, but only 15% of DNA and gene were not. Study group on July 14 of the human genome research magazine reported online, they will be more complicated with yeast compares the worms, and the latter is a multicellular organisms found that there was no 40% of the DNA encoding. Then, researchers will again be vertebrates and insects, and compares these creatures are more complex than the worms, and found that, there were more than 66% of DNA contains any code of DNA.
Participate in the research work of Adam biologists Siepel UCSC calculation, the research results about the worm, which is seriously need for them because scientists just two genomes are analyzed. Nonetheless, or think, this Siepel strongly support that such a theory that vertebrates and increase the complexity of biological insects is mainly due to genetic regulation of fine mode
2008年11月22日星期六
Modern plasmid DNA separation
Modern plasmid DNA separation and purification of separation from escherichia coli, since big represented in e. (E.c oli) and molecular biology, from the important status in the E.c oli separation and purification qc Piasmid < > become DNA DNA in recent years over an important topic of centrifugal technology. But the plasmid DNA separation and purification of super fast and centrifugal equipment (speeding centrifuge, turn and accessory) put forward higher request.
E.c oli is typical of prokaryote cells, due to lack of its nuclear prokaryote cells that have cell membranes of the unit can be separated with multiple functions for the components of the regional and local independent system, thus not endometrial cells contain nuclei (nuclear, organelles endoplasmic reticulum, golgi apparatus, body, the lysosome, etc.). Electron micrograph E.c oli two can show the difference between internal areas -- the cytoplasm and nuclear, in their around a layer of thinner outside the plasma membrane and very thick in the cell walls, and some end external attached of free flagellum. Plasmid DNA located in nuclear zone, filaments exist, such filaments in many cases is material very long annular DNA fragments of the secret that folded.
On the microstructure E.c oli to point, the super centrifugal separation and purification plasmid DNA sequence is before the pretreatment of:
E.c oli to use lysozyme, surfactants used to cell Trit, such as SDS X - 100, acetic acid, etc EE membrane pot that DNA, RNA and protein most sedimentation (90%).
Sediment can add TE buffer 10m (MTris - lmMEDTA pH8.0), HCL in - after the protein, and advances to go RNA, Can also be used to protein, speed centrifugation (level, to go to the RNA DNA or DNA fragments.
The plasmid DNA separation method of speeding.
The traditional separation method: a few years ago by equipment, plasmid DNA restriction of general use CsCl balance, separated from forming gradient centrifugation, density. With 10 ~ 12ml single capacity, for example, in turn, sling flat 36.000 RPM separated by 60 hours with Angle type head, 45, separation, the former inter OOOrpm 36 hours, including deceleration share to 1.3 billion of life, the latter to drive to use to 1 million to drive, the ministry of life at speed centrifuge total lifespan of 100 to 200 million each turn, undoubtedly, plus high cost experiment, the price of your CsCl dosage, make this type of factors such as the separation and purification of experimental work become very expensive.
E.c oli is typical of prokaryote cells, due to lack of its nuclear prokaryote cells that have cell membranes of the unit can be separated with multiple functions for the components of the regional and local independent system, thus not endometrial cells contain nuclei (nuclear, organelles endoplasmic reticulum, golgi apparatus, body, the lysosome, etc.). Electron micrograph E.c oli two can show the difference between internal areas -- the cytoplasm and nuclear, in their around a layer of thinner outside the plasma membrane and very thick in the cell walls, and some end external attached of free flagellum. Plasmid DNA located in nuclear zone, filaments exist, such filaments in many cases is material very long annular DNA fragments of the secret that folded.
On the microstructure E.c oli to point, the super centrifugal separation and purification plasmid DNA sequence is before the pretreatment of:
E.c oli to use lysozyme, surfactants used to cell Trit, such as SDS X - 100, acetic acid, etc EE membrane pot that DNA, RNA and protein most sedimentation (90%).
Sediment can add TE buffer 10m (MTris - lmMEDTA pH8.0), HCL in - after the protein, and advances to go RNA, Can also be used to protein, speed centrifugation (level, to go to the RNA DNA or DNA fragments.
The plasmid DNA separation method of speeding.
The traditional separation method: a few years ago by equipment, plasmid DNA restriction of general use CsCl balance, separated from forming gradient centrifugation, density. With 10 ~ 12ml single capacity, for example, in turn, sling flat 36.000 RPM separated by 60 hours with Angle type head, 45, separation, the former inter OOOrpm 36 hours, including deceleration share to 1.3 billion of life, the latter to drive to use to 1 million to drive, the ministry of life at speed centrifuge total lifespan of 100 to 200 million each turn, undoubtedly, plus high cost experiment, the price of your CsCl dosage, make this type of factors such as the separation and purification of experimental work become very expensive.
Appraisal parenthood
Appraisal parenthood currently use most of the DNA of identification. Is A person's blood, hair, saliva, oral cells can be used in parent-child etc., is very convenient. One of the 23 chromosomes (46), the same chromosome the same position as a pair of genetic alleles, usually one from the father, and from the mother. A If a DNA test to the site, a mother alleles, another can be the same with the father, or a question.
Using DNA in parent-child identification, just as ten to dozens of DNA test, if all sites, can be used to determine if a child, above 3 different sites, exclude parenthood, one or two different sites, should consider the gene mutations can do some sites, plus the check. DNA parent-child relationship, the accuracy of negation parent-child relationship, nearly 100% accuracy of the child reaches got.
DNA tests of common problem child identification
What is the child of DNA tests identified?
DNA (deoxyribonucleic acid) is personal cells in the body of the atomic matter. Each atom is 46 chromosomes, in addition, men and women's eggs sperm cells, each with 23 chromosomes, when sperm and egg combination. This 46 atomic chromosome is a life, therefore, each from his inherited half of molecules, and the other half from birth place.
DNA parent-child appraisal test and the traditional blood test is quite different. It may be in different samples, including blood tests on the cheek, cells, tissue cells cavity sample and semen samples. Due to blood types, such as A type, type B, type O or RH type, in the crowd, used to distinguish comparison of every man, but not valid identification of DNA tests child. Besides, the real twins each DNA is unique because it is so unique. Like fingerprint identification, child, used to be the most effective method of DNA. Our results are usually required than court accurate 10 to 100 times.
The identification of the parent accuracy
DNA parent-child appraisal is the most accurate identification method, if the child QinQuan genetic loci and tested the man (at least 1) sites, so the man inconsistent and 100% excluded, namely consanguinity absolutely impossible, he is the father of the child. If children and parents are the sites, we can draw the possibility of greater QinQuan relations, namely that got the kinship relations between them kiss.
Parent: (1) was identified notice shall be designated by the mother - the son - suspicious father or the parents and children - father or mother only two people generally not accepting JianDingZhe, (2) per adult consent to be identified, 12 years of teenagers should be appropriate to the identification of the opinion, (3) by expert should know his near relatives or any genetic history, (4) age generally identified children aged in half as well, (5) amniotic fluid or fluffy for pregnant women and suspected child appraisal shall be signed by identifying the father aggrement.
Using DNA in parent-child identification, just as ten to dozens of DNA test, if all sites, can be used to determine if a child, above 3 different sites, exclude parenthood, one or two different sites, should consider the gene mutations can do some sites, plus the check. DNA parent-child relationship, the accuracy of negation parent-child relationship, nearly 100% accuracy of the child reaches got.
DNA tests of common problem child identification
What is the child of DNA tests identified?
DNA (deoxyribonucleic acid) is personal cells in the body of the atomic matter. Each atom is 46 chromosomes, in addition, men and women's eggs sperm cells, each with 23 chromosomes, when sperm and egg combination. This 46 atomic chromosome is a life, therefore, each from his inherited half of molecules, and the other half from birth place.
DNA parent-child appraisal test and the traditional blood test is quite different. It may be in different samples, including blood tests on the cheek, cells, tissue cells cavity sample and semen samples. Due to blood types, such as A type, type B, type O or RH type, in the crowd, used to distinguish comparison of every man, but not valid identification of DNA tests child. Besides, the real twins each DNA is unique because it is so unique. Like fingerprint identification, child, used to be the most effective method of DNA. Our results are usually required than court accurate 10 to 100 times.
The identification of the parent accuracy
DNA parent-child appraisal is the most accurate identification method, if the child QinQuan genetic loci and tested the man (at least 1) sites, so the man inconsistent and 100% excluded, namely consanguinity absolutely impossible, he is the father of the child. If children and parents are the sites, we can draw the possibility of greater QinQuan relations, namely that got the kinship relations between them kiss.
Parent: (1) was identified notice shall be designated by the mother - the son - suspicious father or the parents and children - father or mother only two people generally not accepting JianDingZhe, (2) per adult consent to be identified, 12 years of teenagers should be appropriate to the identification of the opinion, (3) by expert should know his near relatives or any genetic history, (4) age generally identified children aged in half as well, (5) amniotic fluid or fluffy for pregnant women and suspected child appraisal shall be signed by identifying the father aggrement.
dna
In the 1950s, DNA double helix structure have been elucidated, opened a new chapter of life science, science and technology, new era. Then, the molecular mechanism of genetic copy, the genetic code -- DNA genetic information transmission center, as a rule, the basic unit of the genetic blueprint of cell engineering and gene and gene expression is one of the regulation. Thus, people have fully realize the fate of all creatures mastery of DNA, and it is contained in the genes, biological evolution process and the process of life, is different because of different operational track and DNA.
Know the major function and value of DNA, life scientists first thought can in some and closely related to the interests of the human nature in the iron break the law, heredity gene come to school in people with the purpose, treating the genetic fragments from different sources ", "to create new grafting new quality... so, with a full allure of science fiction miraculously become a reality. It happened in the early 1970s.
This scientific technology is miracle. DNA restructuring In 1972, American scientists Paul? The first successful restructuring, the first batch of DNA molecules in the world, marks the DNA restructuring technology -- genetic engineering as modern biology engineering foundation, become the modern biotechnology and life science foundation and the core.
Recombinant DNA techniques of concrete content is using artificial means different sources of a particular gene DNA fragments to restructure, change biology gene types and specific genes as a result of high science and technology.
Came late 1970s, because the engineering bacteria and DNA and have engineering properties of post-processing, genetic engineering or genetic engineering as DNA restructuring synonymous with technology is widely used. Now, genetic engineering, include the genome sequence analysis, nucleic acid molecular evolution analysis, molecular immunology, gene cloning, genetic diagnosis and gene therapy, etc. Say, DNA founded nearly 30 years restructuring technology to the great achievements obtained by the people have the incredible fantastic science, won the world of human life and preventing and treating illnesses open secrets "box" key.
Currently, DNA restructuring technology has many achievements. Recombinant DNA of the 20th century, to the largest technology applications in medicine, including active protein and vaccine peptide, the production, the disease occurrence mechanism, diagnosis and treatment of separation, new genes and environment monitoring and purification.
Many active peptides and proteins with treatment and prevention of diseases, they are from the corresponding gene. But due to the organization cells, so using yield a conventional methods to get enough for the clinical application.
Genetic engineering is a breakthrough in the limitations, to this kind of peptides and proteins, we have successfully produced in the treatment of diabetes and schizophrenia, leukemia and some insulin resistance of cancer therapeutic entity for treatment of disease, dwarf -- interferon human growth hormone therapy acromegaly and acute pancreatitis suppression of growth hormone release of product factor etc.
Genetic engineering can also will live on the DNA into the antigen such microbes by microorganisms, immunological stress in the host body growth can produce as weak, poison and stimulate doses of antigen long duration. Currently developing genetic engineering vaccine had dozens of many aspects, in dealing with leprosy coli bacteria are against e., pertussis, neisseria gonorrhoeae ShuangQiuJun etc, meningitis, In dealing with hepatitis a virus is for hepatitis b, cytomegalovirus,, herpes simplex, influenza, HIV vaccine... etc. China hepatitis b carriers and hepatitis b patients 1200 million, this situation as more Chinese scientists spurred by successfully developed hepatitis b vaccine made great social benefits and economic benefits.
Antibodies are the body's immune system is one of the main weapon disease resistance, founded in the 1970s monoclonal antibody technique in preventing disease-resistant aspects though plays an important role, but because it is difficult to achieve single RenYuan sex resistance, single resistance in the clinical application of limited. To solve this problem, in recent years, scientists using DNA restructuring technology has gained RenYuan sexual antibody, the antibody can guarantee the antigen and specificity and loyalty, and ensure the normal functions. Currently, there are many such antibodies in clinical trials, such as the resistance of single RenYuan special genetic marker, known as her2 breast cancer has entered the resistance test, Ⅲ period of single resistance RenYuan IGE Ⅱ has entered the period of treatment of asthma experiment.
Antibiotics in the treatment of the disease has played an important role in increasing Numbers, with antibiotics, with traditional methods and new antibiotic that chance. In order to obtain more new antibiotic, using DNA restructuring technology has become an important means of. People have won dozens of genetic engineering "heterozygous" for the clinical application of antibiotic, opening a new treatment.
As noted above mentioned gene engineering peptide, protein, vaccines, antibiotics, not only in drug prevention and control effectively avoid disease, but in some aspects in traditional method is also often similar drugs, thus producing more people.
Human diseases are directly or indirectly related with genes, at the genetic level on the diagnosis and treatment of disease, can achieve diagnostic accuracy of the etiology and primitivism, and can make the diagnosis and treatment of work to high sensitivity and specificity, convenient quickly. Gene level in diagnosis and treatment in professional called gene diagnosis and gene therapy. Currently genetic diagnosis as the fourth generation of clinical diagnosis technology has been widely applied to genetic diseases, cancer, cardiovascular and cerebrovascular diseases, virus disease and parasitic disease germs such diagnosis, And the object of gene therapy is through DNA restructuring specific functions of the technology to create a genetic recombination, to make up for lost, the function of genes, and to increase or a correction or abnormal cells.
In theory, gene therapy is ZhiBen cured without any adverse effects of therapy. However, although has more than 100 international gene therapy scheme is in clinical trials, but the gene therapy in theory and technology of some problems still make this treatment from the large scale application and a long distance. Whether the gene causes or implementation of genetic diagnosis, gene therapy, research mechanism, the disease is the key to understand the prerequisites for specific diseases related gene. With the human genome project ", "the scientists to human genes will get all the comprehensive understanding, which is formed by genetic restructuring to human health technology to create the conditions.
However, though genetic technology to human shows its fantastic "magic" as the charm, but also has a large number of scientists to this technology development and ecological ethic evolution to the human nature impact showed great concern. Theoretically, this technology is to make the development of a perfection of human have created any life forms or never had the ability of biology. People can imagine how this will be the result?
Scientists in DNA found outside the genetic code unless the new password
According to reports, the United States and Taiwan, they have Israeli scientists believe in DNA (to liu, except the genetic code) found outside the second password. New password for decision -- namely nuclear body of DNA protein surrounded by the position (--. The reel and protection and control of the way to DNA itself.
The findings could open, if that higher rates of relevant control mechanism of genetic information. For example, every kind of human cells to activate the genes needed, but can't touch other kinds of genes, used by cells is the key and mysterious process.
The institute of w) stuffed with America, northwestern university of Wisconsin meal and colleagues in the issue of "natural" scientific journals in writing, described the new password DNA.
Each individual cells are engaged in SanQianWanGe nuclear body. The nuclei are needed so much, because each line of DNA coated paper. Only a nuclear body, each DNA contains hundred units of a spiral of chromosomes, and a single DNA molecules in length may have as a unit 225 million.
Biologists have suspected for years, some of the DNA, especially those most easily bend DNA, may be more advantageous than other position of nuclear, but overall pattern is not obvious. Nowadays, dr wylton liger and analyzed approximately 200 position within the yeast gene sequence, these are both known nuclear body intertwined, they found a really exist hidden.
Through the understanding of this model, their successful predictions about five other organisms nucleation body position. This model is more easily bend can make DNA, and close the bag check two sequences. But in this mode, every body position of nuclear intertwine only several sequence, so it doesn't appear. Because of its formation conditions are loose and therefore does not conflict with the genetic code.
Know the major function and value of DNA, life scientists first thought can in some and closely related to the interests of the human nature in the iron break the law, heredity gene come to school in people with the purpose, treating the genetic fragments from different sources ", "to create new grafting new quality... so, with a full allure of science fiction miraculously become a reality. It happened in the early 1970s.
This scientific technology is miracle. DNA restructuring In 1972, American scientists Paul? The first successful restructuring, the first batch of DNA molecules in the world, marks the DNA restructuring technology -- genetic engineering as modern biology engineering foundation, become the modern biotechnology and life science foundation and the core.
Recombinant DNA techniques of concrete content is using artificial means different sources of a particular gene DNA fragments to restructure, change biology gene types and specific genes as a result of high science and technology.
Came late 1970s, because the engineering bacteria and DNA and have engineering properties of post-processing, genetic engineering or genetic engineering as DNA restructuring synonymous with technology is widely used. Now, genetic engineering, include the genome sequence analysis, nucleic acid molecular evolution analysis, molecular immunology, gene cloning, genetic diagnosis and gene therapy, etc. Say, DNA founded nearly 30 years restructuring technology to the great achievements obtained by the people have the incredible fantastic science, won the world of human life and preventing and treating illnesses open secrets "box" key.
Currently, DNA restructuring technology has many achievements. Recombinant DNA of the 20th century, to the largest technology applications in medicine, including active protein and vaccine peptide, the production, the disease occurrence mechanism, diagnosis and treatment of separation, new genes and environment monitoring and purification.
Many active peptides and proteins with treatment and prevention of diseases, they are from the corresponding gene. But due to the organization cells, so using yield a conventional methods to get enough for the clinical application.
Genetic engineering is a breakthrough in the limitations, to this kind of peptides and proteins, we have successfully produced in the treatment of diabetes and schizophrenia, leukemia and some insulin resistance of cancer therapeutic entity for treatment of disease, dwarf -- interferon human growth hormone therapy acromegaly and acute pancreatitis suppression of growth hormone release of product factor etc.
Genetic engineering can also will live on the DNA into the antigen such microbes by microorganisms, immunological stress in the host body growth can produce as weak, poison and stimulate doses of antigen long duration. Currently developing genetic engineering vaccine had dozens of many aspects, in dealing with leprosy coli bacteria are against e., pertussis, neisseria gonorrhoeae ShuangQiuJun etc, meningitis, In dealing with hepatitis a virus is for hepatitis b, cytomegalovirus,, herpes simplex, influenza, HIV vaccine... etc. China hepatitis b carriers and hepatitis b patients 1200 million, this situation as more Chinese scientists spurred by successfully developed hepatitis b vaccine made great social benefits and economic benefits.
Antibodies are the body's immune system is one of the main weapon disease resistance, founded in the 1970s monoclonal antibody technique in preventing disease-resistant aspects though plays an important role, but because it is difficult to achieve single RenYuan sex resistance, single resistance in the clinical application of limited. To solve this problem, in recent years, scientists using DNA restructuring technology has gained RenYuan sexual antibody, the antibody can guarantee the antigen and specificity and loyalty, and ensure the normal functions. Currently, there are many such antibodies in clinical trials, such as the resistance of single RenYuan special genetic marker, known as her2 breast cancer has entered the resistance test, Ⅲ period of single resistance RenYuan IGE Ⅱ has entered the period of treatment of asthma experiment.
Antibiotics in the treatment of the disease has played an important role in increasing Numbers, with antibiotics, with traditional methods and new antibiotic that chance. In order to obtain more new antibiotic, using DNA restructuring technology has become an important means of. People have won dozens of genetic engineering "heterozygous" for the clinical application of antibiotic, opening a new treatment.
As noted above mentioned gene engineering peptide, protein, vaccines, antibiotics, not only in drug prevention and control effectively avoid disease, but in some aspects in traditional method is also often similar drugs, thus producing more people.
Human diseases are directly or indirectly related with genes, at the genetic level on the diagnosis and treatment of disease, can achieve diagnostic accuracy of the etiology and primitivism, and can make the diagnosis and treatment of work to high sensitivity and specificity, convenient quickly. Gene level in diagnosis and treatment in professional called gene diagnosis and gene therapy. Currently genetic diagnosis as the fourth generation of clinical diagnosis technology has been widely applied to genetic diseases, cancer, cardiovascular and cerebrovascular diseases, virus disease and parasitic disease germs such diagnosis, And the object of gene therapy is through DNA restructuring specific functions of the technology to create a genetic recombination, to make up for lost, the function of genes, and to increase or a correction or abnormal cells.
In theory, gene therapy is ZhiBen cured without any adverse effects of therapy. However, although has more than 100 international gene therapy scheme is in clinical trials, but the gene therapy in theory and technology of some problems still make this treatment from the large scale application and a long distance. Whether the gene causes or implementation of genetic diagnosis, gene therapy, research mechanism, the disease is the key to understand the prerequisites for specific diseases related gene. With the human genome project ", "the scientists to human genes will get all the comprehensive understanding, which is formed by genetic restructuring to human health technology to create the conditions.
However, though genetic technology to human shows its fantastic "magic" as the charm, but also has a large number of scientists to this technology development and ecological ethic evolution to the human nature impact showed great concern. Theoretically, this technology is to make the development of a perfection of human have created any life forms or never had the ability of biology. People can imagine how this will be the result?
Scientists in DNA found outside the genetic code unless the new password
According to reports, the United States and Taiwan, they have Israeli scientists believe in DNA (to liu, except the genetic code) found outside the second password. New password for decision -- namely nuclear body of DNA protein surrounded by the position (--. The reel and protection and control of the way to DNA itself.
The findings could open, if that higher rates of relevant control mechanism of genetic information. For example, every kind of human cells to activate the genes needed, but can't touch other kinds of genes, used by cells is the key and mysterious process.
The institute of w) stuffed with America, northwestern university of Wisconsin meal and colleagues in the issue of "natural" scientific journals in writing, described the new password DNA.
Each individual cells are engaged in SanQianWanGe nuclear body. The nuclei are needed so much, because each line of DNA coated paper. Only a nuclear body, each DNA contains hundred units of a spiral of chromosomes, and a single DNA molecules in length may have as a unit 225 million.
Biologists have suspected for years, some of the DNA, especially those most easily bend DNA, may be more advantageous than other position of nuclear, but overall pattern is not obvious. Nowadays, dr wylton liger and analyzed approximately 200 position within the yeast gene sequence, these are both known nuclear body intertwined, they found a really exist hidden.
Through the understanding of this model, their successful predictions about five other organisms nucleation body position. This model is more easily bend can make DNA, and close the bag check two sequences. But in this mode, every body position of nuclear intertwine only several sequence, so it doesn't appear. Because of its formation conditions are loose and therefore does not conflict with the genetic code.
2008年11月10日星期一
人类遗传变异
五六万年前的这群人，为什么要离开位于非洲东部的家乡？确切原因至今仍是一个谜，可能因为气候发生变化，或者曾经丰富的贝壳类食物的数量突然锐减，才迫使他们向其他大陆迁移。不过有一点是肯定的：这批最早离开非洲的早期人类，已具有现代人的体质和行为特征——较大的脑容量和较强的语言交流能力。抵达亚洲大陆后（登陆点是今天的也门），现代人类的先祖们在此后上万年的时间里，继续向其他大陆进发，直至来到位于南美洲最南端的火地岛（Tierra del Fuego），才停下了脚步。
对人类的起源，科学家已从人类骨骼化石中有所了解，但祖先们遗留下来的实物太少，很难据此描绘出那段遥远历史的全景图。过去20 年间，人类遗传学家利用DNA 分析法，寻找早期人类迁移的证据，以填补古人类学的空白。
对所有人而言， 细胞内的DNA 有99.9％都是相同的，但就是这不同的0.1％，致使个体间的体质特征出现极大的差异。如果比较东非人与美洲土著人的DNA，科学家能从中得到人类世系，以及不同族群在各个大陆间迁徙的重要线索。遗传学家以前认为，只有父亲传递给儿子，或者母亲遗传给孩子的DNA，才具有化石般的研究价值，但最新研究改变了他们的看法，也让他们的关注点，从少部分DNA 片段扩大到整个人类基因组中的数万个核苷酸。
通过对人类基因组的研究，科学家提出了一些早期人类的迁移路径，其中一些在最近几个月才发表出来。这些研究进一步证实，现代人类起源于非洲。这也让人们认识到，遗传多样性是如何从非洲大陆发源，并扩散到世界其他地方的。如果把人类世系看作一棵“进化树”，“树根”就是非洲原著民桑人（San people），最新长出的“树枝”则是南美洲的印第安人和太平洋岛上的居民。
对人类遗传变异的研究，最早可以追溯到第一次世界大战。当时，两名在希腊塞萨洛尼基工作的医生发现，驻守该城士兵的血型为某种特定血型的概率，与他们的国籍有很大的关系。由于蛋白质差异可以反映相应基因的变化，因此，从上世纪50 年代开始，意大利人类遗传学家路易吉·卢卡·卡瓦利－斯福扎（Luigi Luca Cavalli-Sforza）通过检查血型蛋白来规范不同人群间的遗传差异研究。
1987 年，美国加利福尼亚大学伯克利分校的丽贝卡·L·卡恩（Rebecca L. Cann）和艾伦·C·威尔逊（Allan C. Wilson）基于线粒体DNA 的分析结果，发表了一篇震惊世界的论文：两位科学家在论文中指出，由于线粒体DNA 只会由母亲遗传给后代，他们经过研究发现，所有人的祖先都可追踪到一位生活在距今20 万年前的非洲女性身上。全球各大媒体争相报道这一重大发现，并声称现代人类的祖先就是那位“非洲夏娃”（这里说的“夏娃”并非《圣经》中的夏娃，她不是人类历史上的首位女性，而是指现有人类都是她的后代）。
对人类的起源，科学家已从人类骨骼化石中有所了解，但祖先们遗留下来的实物太少，很难据此描绘出那段遥远历史的全景图。过去20 年间，人类遗传学家利用DNA 分析法，寻找早期人类迁移的证据，以填补古人类学的空白。
对所有人而言， 细胞内的DNA 有99.9％都是相同的，但就是这不同的0.1％，致使个体间的体质特征出现极大的差异。如果比较东非人与美洲土著人的DNA，科学家能从中得到人类世系，以及不同族群在各个大陆间迁徙的重要线索。遗传学家以前认为，只有父亲传递给儿子，或者母亲遗传给孩子的DNA，才具有化石般的研究价值，但最新研究改变了他们的看法，也让他们的关注点，从少部分DNA 片段扩大到整个人类基因组中的数万个核苷酸。
通过对人类基因组的研究，科学家提出了一些早期人类的迁移路径，其中一些在最近几个月才发表出来。这些研究进一步证实，现代人类起源于非洲。这也让人们认识到，遗传多样性是如何从非洲大陆发源，并扩散到世界其他地方的。如果把人类世系看作一棵“进化树”，“树根”就是非洲原著民桑人（San people），最新长出的“树枝”则是南美洲的印第安人和太平洋岛上的居民。
对人类遗传变异的研究，最早可以追溯到第一次世界大战。当时，两名在希腊塞萨洛尼基工作的医生发现，驻守该城士兵的血型为某种特定血型的概率，与他们的国籍有很大的关系。由于蛋白质差异可以反映相应基因的变化，因此，从上世纪50 年代开始，意大利人类遗传学家路易吉·卢卡·卡瓦利－斯福扎（Luigi Luca Cavalli-Sforza）通过检查血型蛋白来规范不同人群间的遗传差异研究。
1987 年，美国加利福尼亚大学伯克利分校的丽贝卡·L·卡恩（Rebecca L. Cann）和艾伦·C·威尔逊（Allan C. Wilson）基于线粒体DNA 的分析结果，发表了一篇震惊世界的论文：两位科学家在论文中指出，由于线粒体DNA 只会由母亲遗传给后代，他们经过研究发现，所有人的祖先都可追踪到一位生活在距今20 万年前的非洲女性身上。全球各大媒体争相报道这一重大发现，并声称现代人类的祖先就是那位“非洲夏娃”（这里说的“夏娃”并非《圣经》中的夏娃，她不是人类历史上的首位女性，而是指现有人类都是她的后代）。
親子鑒定
親子鑒定的基本原理：人類基因組是一個結構十分穩定的體系，同時又是一個變異的體系。在長期的進化過程中，基因組DNA的序列不斷發生變異。這些變異有些被保存下來，導致了不同種族、群體和個體間基因組的差異和多態性，除同卵雙生子外，沒有兩個個體基因組是完全相同的。
親子鑒定是根據人類遺傳學的理論和實踐，從子代和親代的形態構造或生理機能方面的相似特點，分析遺傳特徵，對可疑的父與子或母與子之間的親生關係進行判斷，並作出肯定或否定的結論。法醫學的親子鑒定方法，有血型鑒定，外貌特徵的對比，皮膚紋理的檢查，遺傳疾病的檢查，耳垢的區別，味盲的檢查，以及受孕期、生產期，生殖能力的推斷等
DNA親子鑒定的原理和程序
DNA是從幾滴血, 腮細胞或培養的組織纖內提取而來。用疇素將DNA樣本切成小段, 放進喱膠內, 用電泳槽推動DNA小塊使之分離——最細的在最遠, 最大的最近。之後, 分離開的基因放在尼龍薄膜上, 使用特別的DNA探針去尋找基因, 相同的基因會凝聚於一, 然後,利用特別的染料,在X光的環境下,
便顯示由DNA探針凝聚於一的黑色條碼。小孩這種肉眼可見的條碼很特別，一半與母親的吻合,一半與父親的吻合。這過程重覆幾次,每一種探針用於尋找DNA的不同部位並影成獨特的條碼, 用幾組不同的探針, 可得到超過99.9%的父系或然率或分辨率。
親子鑒定是根據人類遺傳學的理論和實踐，從子代和親代的形態構造或生理機能方面的相似特點，分析遺傳特徵，對可疑的父與子或母與子之間的親生關係進行判斷，並作出肯定或否定的結論。法醫學的親子鑒定方法，有血型鑒定，外貌特徵的對比，皮膚紋理的檢查，遺傳疾病的檢查，耳垢的區別，味盲的檢查，以及受孕期、生產期，生殖能力的推斷等
DNA親子鑒定的原理和程序
DNA是從幾滴血, 腮細胞或培養的組織纖內提取而來。用疇素將DNA樣本切成小段, 放進喱膠內, 用電泳槽推動DNA小塊使之分離——最細的在最遠, 最大的最近。之後, 分離開的基因放在尼龍薄膜上, 使用特別的DNA探針去尋找基因, 相同的基因會凝聚於一, 然後,利用特別的染料,在X光的環境下,
便顯示由DNA探針凝聚於一的黑色條碼。小孩這種肉眼可見的條碼很特別，一半與母親的吻合,一半與父親的吻合。這過程重覆幾次,每一種探針用於尋找DNA的不同部位並影成獨特的條碼, 用幾組不同的探針, 可得到超過99.9%的父系或然率或分辨率。
2008年10月30日星期四
Genetic information is the carrier of DNA
Genetic information is the carrier of DNA, with its own DNA molecules must QinDai templates accurate copy copies, and two allocated to two cells to complete its genetic information carrier, the mission. And DNA double chain structure for maintaining the stability of this kind of genetic material and accuracy are extremely important.
The DNA of (1) reserved copy half
Click on Waston and DNA double helix structure model was just after reproduction of DNA, the discovery of DNA in duplicate process of hydrogen at first base XieXuan enzyme) (through the fracture, the double helix structure, each XieXuan chains for template synthesis of new chain respectively. Since each progeny of DNA from other QinDai chain, a new synthetic, so called retained type (half semiconservative replication).
The cloning process DNA (2)
Double-helix DNA 1. The XieXuan
Results (1) (single DNA conjugated protein binding DNA protein, stranded -- ssbDNA protein),
(2) DNA solution chain enzyme (DNA helicase)
(3) DNA solution chain
2 pieces with half a discrete GangQi. Copy
3 the trigger and terminate. Copying
(3) telomere and telomerase
American indians 1941 through toelke (Mc) is proposed Clintock telomere telomeres (that) the hypothesis of chromosome, there must be a special structure -- telomeres. It is now known chromosome telomere role for at least 2:1) protection against damage, chromosome chromosome stability, 2) and nuclear fiber layers, chromosomes are connected.
The DNA of (1) reserved copy half
Click on Waston and DNA double helix structure model was just after reproduction of DNA, the discovery of DNA in duplicate process of hydrogen at first base XieXuan enzyme) (through the fracture, the double helix structure, each XieXuan chains for template synthesis of new chain respectively. Since each progeny of DNA from other QinDai chain, a new synthetic, so called retained type (half semiconservative replication).
The cloning process DNA (2)
Double-helix DNA 1. The XieXuan
Results (1) (single DNA conjugated protein binding DNA protein, stranded -- ssbDNA protein),
(2) DNA solution chain enzyme (DNA helicase)
(3) DNA solution chain
2 pieces with half a discrete GangQi. Copy
3 the trigger and terminate. Copying
(3) telomere and telomerase
American indians 1941 through toelke (Mc) is proposed Clintock telomere telomeres (that) the hypothesis of chromosome, there must be a special structure -- telomeres. It is now known chromosome telomere role for at least 2:1) protection against damage, chromosome chromosome stability, 2) and nuclear fiber layers, chromosomes are connected.
2008年10月27日星期一
DNA consists
DNA consists of many deoxidization nucleotide sequence according to certain residue, each with 3-5 phosphate ester key of long chain connected. Most of the DNA contains two such long chain, and some results, such as DNA, e. coli X174 suits G4, phage M13 etc. Some DNA, DNA for circular for linear. Mainly contains adenine and guanine and thymine bases cytosine and four bases. In certain types of DNA methylation cytosine, 5 - in a certain extent, which replaced cytosine wheat embryo DNA methylation cytosine 5 - especially rich, up to 6 percent. Moore In some phage, 5 - n-hydroxymethyl cytosine replaced cytosine. The 1940s, hargaff guthrie E.C (that) of different species of DNA bases are different, but the number of adenine is equal to the number of thiamine (= T), guanine is equal to the number of cytosine (G = C), and number of equal to number of pyrimidines). Generally depicted in several layers structure of DNA.
The primary structure of DNA level structure is the base sequence. Gene is a segment of DNA genetic information storage, gene in its base in sequence. 1975 American gilbert W.G (UK) and the sanger ilbert F.S (anger) founded the DNA level structure of rapid determination methods, 1980 year of their chemistry prize. Since then, and constantly improve measurement method, the primary structure of DNA has many established. If people mitochondrial DNA contains a ring that 16569, lambda phage DNA contains a base pairs, rice 48502 134525 containing a base pairs chloroplasts genome, tobacco chloroplasts genome contains 155844 a base pairs, etc. Now, the United States has 10 to 15 years in human DNA molecules in about 30 billion for all nucleotide sequence of determination.
Secondary structure in 1953, Watson and Crick (Watson) Crick (.) the basic structure of DNA double helix fiber structure, then this is recognized by scientists model, and the explanation for replication, and other important transcription process of life. For the further research, humidity and base sequences that etc, DNA double helix can have many types, mainly divided into A and B and Z three categories.
Generally, the closest to the cell B configuration of DNA double helix conformation, it is very similar to model. DNA and RNA molecule - the double helix area and the formation of transcription DNA molecule hybridization RNA conformation close -. Z - DNA to nucleotide dimers for unit, the Lord left to wound is serrated (Z) chain, the name. This configuration for a nucleotide chain of purine cytosine alternate area. In 1989, the American scientists scanning tunneling microscopy method directly observed double-helix DNA double-helix DNA in 1952, Austria, African American biochemist captains E.c hargaff gadamer check (1905 -), the four determination of DNA base, the content of fat poison and found adenocarcinoma of the number of thymine bases, bird whisper fat with equal the number of cytosine. This makes Watson and crick immediately thought of four bases exist between two corresponding relationship, formed the glands and thymine * matching belt whisper, birds and cytosine matching belt whisper.
Senior structure
Three chain DNA (T) DNA -
In the early 1950s Wilkins, according to the X-ray diffraction picture once thought DNA may have 3 chains, then Watson and Crick also have some of the construction of DNA model,. The three chain DNA can be classified into two categories, namely three strands of spiral structure and BaiChunLi etc in 1990 by scanning electron tunneling microscopy techniques observed three strands of ornaments structure."
Three strands of DNA double helix spiral structure is formed on the basis of the structure of the chain, three chains are cognate 3) or homologous thymine bases that whole of purine or cytosine, according to article 3 source of chain can be divided into three chain DNA molecules in between two groups and the molecular chain consisting of three, according to the relative positions and can be divided into the Pu - Pu - Py and Py - Pu Py - two type (Pu generation
Table purine chain, Py represents one of the most common pyrimidines chain is Py - Pu Py - 3, it has two chains for normal double helix, located in article 3 of the double helix pyrimidines chains, and the chains purine ditch, and the direction of the double helix structure rotates with three chain base pairing with the same way, double-helix DNA base on A - it is still, G - C matching T, but the first 3 chain of C, and it must be formed with only 2 hydrogen G (normally three hydrogen).
Three chains to the further study of DNA to eukaryotic chromosomes structure and the gene transcriptional regulation and restructuring, copying, the mechanism. Three chain of DNA is available, such as application value liquid.thus DNA fragments will cut (such as the nucleic acid enzymes) carry specific locus of DNA, and to achieve a break, and the purpose of chromosomes of DNA cells for transcription factors etc. double-helix DNA and protein only after the combination can open the specific gene transcription, but three strands and transcription factors, thus available spiral oligonucleotides gather DNA fragments of the closed transcription factor sites, so as to achieve closed harmful genes or virus gene.
Four chain body DNA
In the simulated Sundpuist Klug and 1 protoctistans spines caterpillars telomeres, synthetic DNA sequence of DNA 1, found in certain conditions of simulation results can be formed DNA G four chain structure of DNA body. Hence infer telomere liquid.thus the chromosome chain between four and formed. Such people with Kang respectively in the crystal and experiments, rich in the solution to four DNA G chain structure of DNA body.
Four basic structure of DNA chain body is G - 4 in four conjoined twin conjoined twins, the center is one of four with negative oxygen into the "carboxylic through G - 4 pocket" of conjoined twins or molecules can form of DNA double helix, and right spiral structure of conjoined twins, G - 4 with two spiral distinct characteristics: 1, it depends on the stability of cation in pocket, known species of k to four conjoined twin screw is the most stable, 2, thermodynamics and kinetics of its nature is very stable.
As for some biological sequences of DNA analysis and guanine sequences of DNA in some in function and evolution of the genome are fairly conservative regional, many studies show that rich guanine DNA formed G - as molecular DNA may mutual recognition of the components in biological cells, plays a special role
The primary structure of DNA level structure is the base sequence. Gene is a segment of DNA genetic information storage, gene in its base in sequence. 1975 American gilbert W.G (UK) and the sanger ilbert F.S (anger) founded the DNA level structure of rapid determination methods, 1980 year of their chemistry prize. Since then, and constantly improve measurement method, the primary structure of DNA has many established. If people mitochondrial DNA contains a ring that 16569, lambda phage DNA contains a base pairs, rice 48502 134525 containing a base pairs chloroplasts genome, tobacco chloroplasts genome contains 155844 a base pairs, etc. Now, the United States has 10 to 15 years in human DNA molecules in about 30 billion for all nucleotide sequence of determination.
Secondary structure in 1953, Watson and Crick (Watson) Crick (.) the basic structure of DNA double helix fiber structure, then this is recognized by scientists model, and the explanation for replication, and other important transcription process of life. For the further research, humidity and base sequences that etc, DNA double helix can have many types, mainly divided into A and B and Z three categories.
Generally, the closest to the cell B configuration of DNA double helix conformation, it is very similar to model. DNA and RNA molecule - the double helix area and the formation of transcription DNA molecule hybridization RNA conformation close -. Z - DNA to nucleotide dimers for unit, the Lord left to wound is serrated (Z) chain, the name. This configuration for a nucleotide chain of purine cytosine alternate area. In 1989, the American scientists scanning tunneling microscopy method directly observed double-helix DNA double-helix DNA in 1952, Austria, African American biochemist captains E.c hargaff gadamer check (1905 -), the four determination of DNA base, the content of fat poison and found adenocarcinoma of the number of thymine bases, bird whisper fat with equal the number of cytosine. This makes Watson and crick immediately thought of four bases exist between two corresponding relationship, formed the glands and thymine * matching belt whisper, birds and cytosine matching belt whisper.
Senior structure
Three chain DNA (T) DNA -
In the early 1950s Wilkins, according to the X-ray diffraction picture once thought DNA may have 3 chains, then Watson and Crick also have some of the construction of DNA model,. The three chain DNA can be classified into two categories, namely three strands of spiral structure and BaiChunLi etc in 1990 by scanning electron tunneling microscopy techniques observed three strands of ornaments structure."
Three strands of DNA double helix spiral structure is formed on the basis of the structure of the chain, three chains are cognate 3) or homologous thymine bases that whole of purine or cytosine, according to article 3 source of chain can be divided into three chain DNA molecules in between two groups and the molecular chain consisting of three, according to the relative positions and can be divided into the Pu - Pu - Py and Py - Pu Py - two type (Pu generation
Table purine chain, Py represents one of the most common pyrimidines chain is Py - Pu Py - 3, it has two chains for normal double helix, located in article 3 of the double helix pyrimidines chains, and the chains purine ditch, and the direction of the double helix structure rotates with three chain base pairing with the same way, double-helix DNA base on A - it is still, G - C matching T, but the first 3 chain of C, and it must be formed with only 2 hydrogen G (normally three hydrogen).
Three chains to the further study of DNA to eukaryotic chromosomes structure and the gene transcriptional regulation and restructuring, copying, the mechanism. Three chain of DNA is available, such as application value liquid.thus DNA fragments will cut (such as the nucleic acid enzymes) carry specific locus of DNA, and to achieve a break, and the purpose of chromosomes of DNA cells for transcription factors etc. double-helix DNA and protein only after the combination can open the specific gene transcription, but three strands and transcription factors, thus available spiral oligonucleotides gather DNA fragments of the closed transcription factor sites, so as to achieve closed harmful genes or virus gene.
Four chain body DNA
In the simulated Sundpuist Klug and 1 protoctistans spines caterpillars telomeres, synthetic DNA sequence of DNA 1, found in certain conditions of simulation results can be formed DNA G four chain structure of DNA body. Hence infer telomere liquid.thus the chromosome chain between four and formed. Such people with Kang respectively in the crystal and experiments, rich in the solution to four DNA G chain structure of DNA body.
Four basic structure of DNA chain body is G - 4 in four conjoined twin conjoined twins, the center is one of four with negative oxygen into the "carboxylic through G - 4 pocket" of conjoined twins or molecules can form of DNA double helix, and right spiral structure of conjoined twins, G - 4 with two spiral distinct characteristics: 1, it depends on the stability of cation in pocket, known species of k to four conjoined twin screw is the most stable, 2, thermodynamics and kinetics of its nature is very stable.
As for some biological sequences of DNA analysis and guanine sequences of DNA in some in function and evolution of the genome are fairly conservative regional, many studies show that rich guanine DNA formed G - as molecular DNA may mutual recognition of the components in biological cells, plays a special role
2008年10月23日星期四
The physicochemical properties of DNA
The physicochemical properties of DNA.
DNA is macromolecules polymer solution for polymer solution, DNA, has high viscosity. DNA to absorb uv, when there was light nucleic acid degeneration increase value, When the degeneration KeFuXing nucleic acid value, and will return to their former level. Temperature, organic solvents, ph, urea, amide, can cause the DNA molecule reagent, even to DNA double fracture of the double helix structure, hydrogen.
Deoxyribonucleic acid (DNA) refers to deoxyribonucleic acid (chromosomes and genetic component of deoxidizing), is the main properties chromosomes. Genetic information is stored in most parts of the DNA molecules.
This period of the distribution and editing functions.
Prokaryote cells chromosome is a long DNA molecules. The nucleus of more than one chromosomes, each containing a chromosome and only DNA molecules. But they usually prokaryote cells than the DNA molecule and large and protein together. DNA molecule function is stored decided all species of protein and RNA structure; all the genetic information, Planning is the synthesis of biological sequence components of cells and tissues of space and time, Biological throughout life cycle of activity and biological character. Besides chromosomes are a DNA, the structure of DNA exist in eukaryotic cells in the mitochondria and chloroplasts. DNA genetic material is the virus DNA.
This section of the DNA editor that.
Since Mendelian genetics was rediscovered, law of people and put forward a problem: genetic factor is a tangible? In order to solve the problem, it is something genes and proteins of nucleic acids was started.
Early in 1868, it has been discovered the nucleic acid. In Germany, the chemist HuoPei of lab, a graduate of Switzerland (1844 - named michelle, his lab 1895) to throw a nearby hospital with the bandage NongXie interested, because he knows that NongXie is to defend human health, and bacteria "combat" died and was killed and the white body cell "body". So he took the bandage carefully NongXie collected and decomposing pepsin, found that most of the body cells are decomposed, but to nuclei. He further analysis of nuclear material, found within the nucleus contains a rich phosphorus and nitrogen. The yeast, caleb HuoPei experimenting with that of nuclear material michel within that is correct. Then he gave the separated from the nucleus of material named ", "people later found nuclide acid, so it is often called" the nucleic acid. From then on, people of nucleic acid has conducted a series of effective research.
At the beginning of the 20th century, Germany, Serbia (1853, 1927) and his two students Jones (1865-1935) and 1940) -- lieven 1869 (the nucleic acid, the study of basic chemical structure, think it is composed by many nucleotides of molecules. Nucleotide bases, DNA is composed of phosphate. And There are four bases of adenocarcinoma, mere (Piao birds, and thymine bases cytosine), there are two (DNA), therefore, deoxyribose the nucleic acid into ribonucleic acid (DNA or RNA) (DNA).
Levin anxious about his research, mistakenly believe that four bases in the nucleic acid, which is equal to deduce the basic structure of nucleic acids by four different bases of nucleotides linked to four nucleotide, and based on this, put forward the nucleic acid polymer into four nucleotide hypothesis. "," This error, to understand the complex hypothesis of the structure of nucleic acid is in effect, and to a certain extent of nucleic acid functions of people. People think that although the nucleic acid exists in important structure -- the nucleus, but its structure, it is hard to imagine that it is too simple genetic process in what role.
Protein found in 30 years earlier than the nucleic acid, is developing rapidly. In the 20th century, when the 20 amino acids in the protein have 12 was found, to all that was in 1940.
In 1902, German chemist's fee from between amino acids proposed by peptide chains and protein linking the theory, 1917 he was synthesized by 15 glycine and 3 LiangAnSuan consist of 18 peptide chains of. So, some scientists, probably in genetic. If the nucleic acid in genetic, must be together with the proteins in the nucleoprotein. Therefore, when nature common tend to think that protein is the carrier of genetic information.
In 1928, American scientists grievous (1941) in 1877 - a JiaMo, strong and a toxic JiaMo without toxic weak ShuangQiuJun pneumonia, the mouse experiment. He has to kill bacteria in high after the pod and live together with the pod bacteria, the mice who note that he died, mouse soon onset of blood from his mice had lived there pod germs. This shows that bacteria from death without pod of bacteria have gained in any pod, no matter for a pod into pod. This hypothesis is correct? Grievous in test tubes, the experiments have found dead and live without beauty in a test tube simultaneously pod bacteria, fungi all become without pod, and found there pod that bacteria grow without pod protein pod is dead are left in the shell pod bacteria in the nucleic acid (because of the heat, pod and no nucleic acid). Grievous said the nucleic acid as "transformation factor".
In 1944, the United States bacteriologist Avery (1877-1955) from a beautiful bacteria isolated activity, "and" transformation factor for this matter do inspection protein, the test whether there is negative, and prove "transformation factor" is the DNA. But this is widely acknowledged that no doubt, people can cleanse protein of technology, has transformed the residue of protein.
American scientists del cloth luc (1906-1981) found in Avery phage group. Because they came in electronic microscope phage form and enter the growth of e. coli. Phages are bacteria for the host cell in the form of a virus that individuals with electron microscope, only to see them. It is like a small tadpoles, external is composed by protein membrane and head of the tail scabbard, head, tail DNA contains the scabbard is tail, substrate and small hook. When the phage infect escherichia coli, the tail end in the membrane of bacteria, and then it will all the body to bacterial DNA cells injection, protein to remain in bacteria outside shell, no cells what effect. After the cells into bacteria, using bacteria phage DNA synthesis of the material of phage quickly and DNA and protein, with the original copy out many phage size shape like a new phage, until the bacteria was completely, leaving only these phages died of bacteria, to infect other bacteria.
In 1952, phage group members hirsch (1908) and his students to chase with advanced technology, do 13c-substrate phage infect escherichia coli experiments. He put the e. coli T2), the nucleic acid 32P 35S on protein shell markers. With the first mark e. coli, phage T2 infection and are isolated, results of phage 35S will take mark e. coli outside shell stay inside, only with the phage 32P mark's note meropenem all the nucleic acid, and in e. coli successfully conducted within the phage reproduction. The experiment proved that DNA has passed, and the function of the genetic information from the DNA protein synthesis of instructions. The results immediately accepted for academic.
Almost at the same time, Austria biochemists chagas - to Cardiff (1905) the four bases of nucleic acids content determination of fruit. Under the influence of the work in Avery, he thinks that if the creature is different because of different DNA, the structure of DNA is complex, or to the biological diversity. Therefore, he told the "four lieven nucleotide hypothesis" created doubts. In 1948-1952 4 years, he took advantage of The Times more accurate than lieven paper chromatography separation four bases, uv absorption spectrum do quantitative analysis, multiple repeated experiments, finally came to a different result. Levin Experimental results show that, in the DNA molecules in the us and thymine Piao the total number of molecules, said A Piao glands and thymine * T equal Piao bird said G and cytosine equal. C, Explain the DNA molecule with T, G, A base pairs of existence with C is negative, and four nucleotide hypothesis ", "and to explore the DNA molecule structure provides important clues and basis.
On April 25, 1953, Britain's nature magazine published the Watson and crick in Britain at the university of Cambridge research achievements of cooperation of the double helix structure of DNA molecules, and this result later model since the 20th century as the greatest discovery of biology, marks the birth of molecular biology.
Watson (1928) in a middle school is a very clever boy, at the age of 15 entered university of Chicago. At that time, because the early allowed a human, experimental education plan from aspects of chance Watson studying biological science course completely. In college, Watson in genetics, though few aspects have a formal training, but since starting the read your life? What is the physical appearance, living cells newcomb, prompting him to find the secret of genes. He is so long, all contribute to the ideas of others with good enrich himself. As long as there is convenient conditions, don't force yourself to learn the new field, can get the knowledge needed. Dr. Watson 22 degrees, and obtained by studying postdoctoral fellow to Europe. In order to fully clear a virus gene chemical structure, to study chemistry lab Copenhagen, Denmark. He once and mentor to Italy in a biological macromolecules napoli have chance to listen to English conference, physical biologists wilkings showed (1916) speech -- see wilkings showed pictures of DNAX ray diffraction. Since then, the structure of DNA for loose in the key ideas in the mind of Watson claims. Where can I learn analysis X-ray diffraction figure? So he again to the university of Cambridge's laboratory study, Calvin don&apost know in this period. Watson post-lava creek
Crick (MCA) a 2004 in 1916, scientific accomplishment of passion in 1937, graduated from London university. In 1946, he read the life is? - living cells, the physical appearance of the physics knowledge for determination of biology research, the biology. In 1947, he started a graduate study, 1949, he used together with peruzzi form X-ray protein molecules structure, technical research and so on, met Watson. At age 12 large than Watson post-lava creek, also have doctoral degree. But they talked about is speculative, Watson was here could find a more important than knowing DNA protein, it's a great honor to. While he was in contact with Watson and crick among the people are the most intelligent one. They talk at least for several hours everyday, discusses the academic problems. Two complement each other and criticism of inspiration inspired. They say part of the solution is open genetic structure of DNA molecule mysteries of the key. Only by precise X-ray diffraction data, can quickly out of the structure of DNA. In order to get information, crick DNAX ray diffraction, please come to Cambridge wilkings showed the weekend. In the conversation wilkings showed accepted the spiral structure of DNA is, also spoke of his partners franklin (1920, female) and a 1958 laboratory scientists, the structure of DNA in scratching the model. In 1951, November to 1953 on April 18 months, Watson and crick wilkings showed, with a few times between franklin's academic exchanges is important.
In 1951, November, Watson heard about the structure of DNA franklin after the detailed report, has inspired, crystal structure analysis knowledge Watson and crick soon realized, to establish DNA structure model of others, the analysis of the data. They soon put forward three strands of DNA in a spiral structure. At the end, they please 1951 wilkings showed and franklin to discuss the model, the DNA of Benjamin Franklin pointed out that they were less water, so the first half well established model has failed.
One day, Watson and to the lab, wilkings showed wilkings showed a recently took out of Benjamin Franklin "B type" DNA X-ray diffraction photos. Watson A photos, immediately got excited and heartbeat accelerate, because this is the "image than before A type" as A much simpler, see "B" X-ray diffraction by simple calculation, photos, DNA molecules can be determined in A number of nucleotide chain more.
Crick please help calculation, the results show that the mathematician has attracted the source said the trend pyrimidines. According to the results, and they find Randolph obtained from the nucleic acid with two of us and two thymine Piao two equal results, the concept of base pairing.
They bitterly about four bases of sequence, again and again in the paper bases on the picture, playing with model, and were put to overthrow assumptions, and his assumptions.
Watson and crick (left), Watson and in his own ideas, he put the model base eagerness moved to remove the possibility for various pairing. Suddenly, he found the glands connected by two hydrogen said a thymine bases for belt to and from three hydrogen Piao bird said a connection to the same cytosine, so the shape of the spirit. The number of us because Piao why and thymine exactly the same number of this mystery shall be solved. Check and law at Cardiff with DNA double helix structure into the inevitable result. Therefore, how to as a template synthesis a complementary sequence of chain will base envisioned. Then, two chains skeleton must be the opposite direction.
After Watson and crick continuous work, tension soon finished metal model of DNA. From this model, DNA consists of two nucleotides chains, their central axis in the opposite direction along with each other, like intertwined in a spiral staircase armrest, is more than two sides of sugar a nucleotide chain of phosphorus gene alternately, that is the skeleton step. Due to the lack of accurate information, they also X-ray not judge model is completely correct.
Benjamin Franklin wilkings showed the scientific method is based on the model prediction out and X-ray diffraction experiment data of a serious. They call again had wilkings showed. Within two days, when franklin and wilkings showed with X-ray data analysis of the double helix structure model is proved correct, and wrote two experimental report published in the British journal nature. In 1962, Watson and crick and wilkings showed won the Nobel Prize for physiology and medicine, and for cancer franklin died in 1958 and was awarded the award.
In the 1930s, the Swedish scientists is that the asymmetry of DNA. The second world war by electron microscopy, the determination of the diameter of the DNA molecules out about 2nm.
DNA double helix structure was discovered, greatly shook the academia, inspired people's thoughts. From then on, people immediately to the center of genetics of molecular biology research. First is around four bases coding permutation how to express 20 amino acids centers for experimental study. In 1967, the genetic code are all cracked, gene and so on in the DNA molecule level of new concepts. It shows that the gene is actually a segment of DNA molecules, biological characters is to control the genetic material structure and functions. In this unit of many pieces of nucleotide, but not in any arrangement has implications of the sequence of codes. Certain structure of DNA, can control the protein synthesis of corresponding structures. Protein is an important component of living organisms, biological characters is mainly embodied by protein. Therefore, the control of genes is through the characters of protein synthesis of DNA control. Based on the genetic engineering, after fermentation engineering, enzyme engineering, etc, these creatures protein engineering technology development will make people using biological rules for the benefit of humanity. The development of modern biology, more and more shows its rise to lead to the subject.
DNA is macromolecules polymer solution for polymer solution, DNA, has high viscosity. DNA to absorb uv, when there was light nucleic acid degeneration increase value, When the degeneration KeFuXing nucleic acid value, and will return to their former level. Temperature, organic solvents, ph, urea, amide, can cause the DNA molecule reagent, even to DNA double fracture of the double helix structure, hydrogen.
Deoxyribonucleic acid (DNA) refers to deoxyribonucleic acid (chromosomes and genetic component of deoxidizing), is the main properties chromosomes. Genetic information is stored in most parts of the DNA molecules.
This period of the distribution and editing functions.
Prokaryote cells chromosome is a long DNA molecules. The nucleus of more than one chromosomes, each containing a chromosome and only DNA molecules. But they usually prokaryote cells than the DNA molecule and large and protein together. DNA molecule function is stored decided all species of protein and RNA structure; all the genetic information, Planning is the synthesis of biological sequence components of cells and tissues of space and time, Biological throughout life cycle of activity and biological character. Besides chromosomes are a DNA, the structure of DNA exist in eukaryotic cells in the mitochondria and chloroplasts. DNA genetic material is the virus DNA.
This section of the DNA editor that.
Since Mendelian genetics was rediscovered, law of people and put forward a problem: genetic factor is a tangible? In order to solve the problem, it is something genes and proteins of nucleic acids was started.
Early in 1868, it has been discovered the nucleic acid. In Germany, the chemist HuoPei of lab, a graduate of Switzerland (1844 - named michelle, his lab 1895) to throw a nearby hospital with the bandage NongXie interested, because he knows that NongXie is to defend human health, and bacteria "combat" died and was killed and the white body cell "body". So he took the bandage carefully NongXie collected and decomposing pepsin, found that most of the body cells are decomposed, but to nuclei. He further analysis of nuclear material, found within the nucleus contains a rich phosphorus and nitrogen. The yeast, caleb HuoPei experimenting with that of nuclear material michel within that is correct. Then he gave the separated from the nucleus of material named ", "people later found nuclide acid, so it is often called" the nucleic acid. From then on, people of nucleic acid has conducted a series of effective research.
At the beginning of the 20th century, Germany, Serbia (1853, 1927) and his two students Jones (1865-1935) and 1940) -- lieven 1869 (the nucleic acid, the study of basic chemical structure, think it is composed by many nucleotides of molecules. Nucleotide bases, DNA is composed of phosphate. And There are four bases of adenocarcinoma, mere (Piao birds, and thymine bases cytosine), there are two (DNA), therefore, deoxyribose the nucleic acid into ribonucleic acid (DNA or RNA) (DNA).
Levin anxious about his research, mistakenly believe that four bases in the nucleic acid, which is equal to deduce the basic structure of nucleic acids by four different bases of nucleotides linked to four nucleotide, and based on this, put forward the nucleic acid polymer into four nucleotide hypothesis. "," This error, to understand the complex hypothesis of the structure of nucleic acid is in effect, and to a certain extent of nucleic acid functions of people. People think that although the nucleic acid exists in important structure -- the nucleus, but its structure, it is hard to imagine that it is too simple genetic process in what role.
Protein found in 30 years earlier than the nucleic acid, is developing rapidly. In the 20th century, when the 20 amino acids in the protein have 12 was found, to all that was in 1940.
In 1902, German chemist's fee from between amino acids proposed by peptide chains and protein linking the theory, 1917 he was synthesized by 15 glycine and 3 LiangAnSuan consist of 18 peptide chains of. So, some scientists, probably in genetic. If the nucleic acid in genetic, must be together with the proteins in the nucleoprotein. Therefore, when nature common tend to think that protein is the carrier of genetic information.
In 1928, American scientists grievous (1941) in 1877 - a JiaMo, strong and a toxic JiaMo without toxic weak ShuangQiuJun pneumonia, the mouse experiment. He has to kill bacteria in high after the pod and live together with the pod bacteria, the mice who note that he died, mouse soon onset of blood from his mice had lived there pod germs. This shows that bacteria from death without pod of bacteria have gained in any pod, no matter for a pod into pod. This hypothesis is correct? Grievous in test tubes, the experiments have found dead and live without beauty in a test tube simultaneously pod bacteria, fungi all become without pod, and found there pod that bacteria grow without pod protein pod is dead are left in the shell pod bacteria in the nucleic acid (because of the heat, pod and no nucleic acid). Grievous said the nucleic acid as "transformation factor".
In 1944, the United States bacteriologist Avery (1877-1955) from a beautiful bacteria isolated activity, "and" transformation factor for this matter do inspection protein, the test whether there is negative, and prove "transformation factor" is the DNA. But this is widely acknowledged that no doubt, people can cleanse protein of technology, has transformed the residue of protein.
American scientists del cloth luc (1906-1981) found in Avery phage group. Because they came in electronic microscope phage form and enter the growth of e. coli. Phages are bacteria for the host cell in the form of a virus that individuals with electron microscope, only to see them. It is like a small tadpoles, external is composed by protein membrane and head of the tail scabbard, head, tail DNA contains the scabbard is tail, substrate and small hook. When the phage infect escherichia coli, the tail end in the membrane of bacteria, and then it will all the body to bacterial DNA cells injection, protein to remain in bacteria outside shell, no cells what effect. After the cells into bacteria, using bacteria phage DNA synthesis of the material of phage quickly and DNA and protein, with the original copy out many phage size shape like a new phage, until the bacteria was completely, leaving only these phages died of bacteria, to infect other bacteria.
In 1952, phage group members hirsch (1908) and his students to chase with advanced technology, do 13c-substrate phage infect escherichia coli experiments. He put the e. coli T2), the nucleic acid 32P 35S on protein shell markers. With the first mark e. coli, phage T2 infection and are isolated, results of phage 35S will take mark e. coli outside shell stay inside, only with the phage 32P mark's note meropenem all the nucleic acid, and in e. coli successfully conducted within the phage reproduction. The experiment proved that DNA has passed, and the function of the genetic information from the DNA protein synthesis of instructions. The results immediately accepted for academic.
Almost at the same time, Austria biochemists chagas - to Cardiff (1905) the four bases of nucleic acids content determination of fruit. Under the influence of the work in Avery, he thinks that if the creature is different because of different DNA, the structure of DNA is complex, or to the biological diversity. Therefore, he told the "four lieven nucleotide hypothesis" created doubts. In 1948-1952 4 years, he took advantage of The Times more accurate than lieven paper chromatography separation four bases, uv absorption spectrum do quantitative analysis, multiple repeated experiments, finally came to a different result. Levin Experimental results show that, in the DNA molecules in the us and thymine Piao the total number of molecules, said A Piao glands and thymine * T equal Piao bird said G and cytosine equal. C, Explain the DNA molecule with T, G, A base pairs of existence with C is negative, and four nucleotide hypothesis ", "and to explore the DNA molecule structure provides important clues and basis.
On April 25, 1953, Britain's nature magazine published the Watson and crick in Britain at the university of Cambridge research achievements of cooperation of the double helix structure of DNA molecules, and this result later model since the 20th century as the greatest discovery of biology, marks the birth of molecular biology.
Watson (1928) in a middle school is a very clever boy, at the age of 15 entered university of Chicago. At that time, because the early allowed a human, experimental education plan from aspects of chance Watson studying biological science course completely. In college, Watson in genetics, though few aspects have a formal training, but since starting the read your life? What is the physical appearance, living cells newcomb, prompting him to find the secret of genes. He is so long, all contribute to the ideas of others with good enrich himself. As long as there is convenient conditions, don't force yourself to learn the new field, can get the knowledge needed. Dr. Watson 22 degrees, and obtained by studying postdoctoral fellow to Europe. In order to fully clear a virus gene chemical structure, to study chemistry lab Copenhagen, Denmark. He once and mentor to Italy in a biological macromolecules napoli have chance to listen to English conference, physical biologists wilkings showed (1916) speech -- see wilkings showed pictures of DNAX ray diffraction. Since then, the structure of DNA for loose in the key ideas in the mind of Watson claims. Where can I learn analysis X-ray diffraction figure? So he again to the university of Cambridge's laboratory study, Calvin don&apost know in this period. Watson post-lava creek
Crick (MCA) a 2004 in 1916, scientific accomplishment of passion in 1937, graduated from London university. In 1946, he read the life is? - living cells, the physical appearance of the physics knowledge for determination of biology research, the biology. In 1947, he started a graduate study, 1949, he used together with peruzzi form X-ray protein molecules structure, technical research and so on, met Watson. At age 12 large than Watson post-lava creek, also have doctoral degree. But they talked about is speculative, Watson was here could find a more important than knowing DNA protein, it's a great honor to. While he was in contact with Watson and crick among the people are the most intelligent one. They talk at least for several hours everyday, discusses the academic problems. Two complement each other and criticism of inspiration inspired. They say part of the solution is open genetic structure of DNA molecule mysteries of the key. Only by precise X-ray diffraction data, can quickly out of the structure of DNA. In order to get information, crick DNAX ray diffraction, please come to Cambridge wilkings showed the weekend. In the conversation wilkings showed accepted the spiral structure of DNA is, also spoke of his partners franklin (1920, female) and a 1958 laboratory scientists, the structure of DNA in scratching the model. In 1951, November to 1953 on April 18 months, Watson and crick wilkings showed, with a few times between franklin's academic exchanges is important.
In 1951, November, Watson heard about the structure of DNA franklin after the detailed report, has inspired, crystal structure analysis knowledge Watson and crick soon realized, to establish DNA structure model of others, the analysis of the data. They soon put forward three strands of DNA in a spiral structure. At the end, they please 1951 wilkings showed and franklin to discuss the model, the DNA of Benjamin Franklin pointed out that they were less water, so the first half well established model has failed.
One day, Watson and to the lab, wilkings showed wilkings showed a recently took out of Benjamin Franklin "B type" DNA X-ray diffraction photos. Watson A photos, immediately got excited and heartbeat accelerate, because this is the "image than before A type" as A much simpler, see "B" X-ray diffraction by simple calculation, photos, DNA molecules can be determined in A number of nucleotide chain more.
Crick please help calculation, the results show that the mathematician has attracted the source said the trend pyrimidines. According to the results, and they find Randolph obtained from the nucleic acid with two of us and two thymine Piao two equal results, the concept of base pairing.
They bitterly about four bases of sequence, again and again in the paper bases on the picture, playing with model, and were put to overthrow assumptions, and his assumptions.
Watson and crick (left), Watson and in his own ideas, he put the model base eagerness moved to remove the possibility for various pairing. Suddenly, he found the glands connected by two hydrogen said a thymine bases for belt to and from three hydrogen Piao bird said a connection to the same cytosine, so the shape of the spirit. The number of us because Piao why and thymine exactly the same number of this mystery shall be solved. Check and law at Cardiff with DNA double helix structure into the inevitable result. Therefore, how to as a template synthesis a complementary sequence of chain will base envisioned. Then, two chains skeleton must be the opposite direction.
After Watson and crick continuous work, tension soon finished metal model of DNA. From this model, DNA consists of two nucleotides chains, their central axis in the opposite direction along with each other, like intertwined in a spiral staircase armrest, is more than two sides of sugar a nucleotide chain of phosphorus gene alternately, that is the skeleton step. Due to the lack of accurate information, they also X-ray not judge model is completely correct.
Benjamin Franklin wilkings showed the scientific method is based on the model prediction out and X-ray diffraction experiment data of a serious. They call again had wilkings showed. Within two days, when franklin and wilkings showed with X-ray data analysis of the double helix structure model is proved correct, and wrote two experimental report published in the British journal nature. In 1962, Watson and crick and wilkings showed won the Nobel Prize for physiology and medicine, and for cancer franklin died in 1958 and was awarded the award.
In the 1930s, the Swedish scientists is that the asymmetry of DNA. The second world war by electron microscopy, the determination of the diameter of the DNA molecules out about 2nm.
DNA double helix structure was discovered, greatly shook the academia, inspired people's thoughts. From then on, people immediately to the center of genetics of molecular biology research. First is around four bases coding permutation how to express 20 amino acids centers for experimental study. In 1967, the genetic code are all cracked, gene and so on in the DNA molecule level of new concepts. It shows that the gene is actually a segment of DNA molecules, biological characters is to control the genetic material structure and functions. In this unit of many pieces of nucleotide, but not in any arrangement has implications of the sequence of codes. Certain structure of DNA, can control the protein synthesis of corresponding structures. Protein is an important component of living organisms, biological characters is mainly embodied by protein. Therefore, the control of genes is through the characters of protein synthesis of DNA control. Based on the genetic engineering, after fermentation engineering, enzyme engineering, etc, these creatures protein engineering technology development will make people using biological rules for the benefit of humanity. The development of modern biology, more and more shows its rise to lead to the subject.
2008年10月17日星期五
DNA consists
DNA consists of many deoxidization nucleotide sequence according to certain residue, each with 3-5 phosphate ester key of long chain connected. Most of the DNA contains two such long chain, and some results, such as DNA, e. coli X174 suits G4, phage M13 etc. Some DNA, DNA for circular for linear. Mainly contains adenine and guanine and thymine bases cytosine and four bases. In certain types of DNA methylation cytosine, 5 - in a certain extent, which replaced cytosine wheat embryo DNA methylation cytosine 5 - especially rich, up to 6 percent. Moore In some phage, 5 - n-hydroxymethyl cytosine replaced cytosine. The 1940s, hargaff guthrie E.C (that) of different species of DNA bases are different, but the number of adenine is equal to the number of thiamine (= T), guanine is equal to the number of cytosine (G = C), and number of equal to number of pyrimidines). Generally depicted in several layers structure of DNA.
The primary structure of DNA level structure is the base sequence. Gene is a segment of DNA genetic information storage, gene in its base in sequence. 1975 American gilbert W.G (UK) and the sanger ilbert F.S (anger) founded the DNA level structure of rapid determination methods, 1980 year of their chemistry prize. Since then, and constantly improve measurement method, the primary structure of DNA has many established. If people mitochondrial DNA contains a ring that 16569, lambda phage DNA contains a base pairs, rice 48502 134525 containing a base pairs chloroplasts genome, tobacco chloroplasts genome contains 155844 a base pairs, etc. Now, the United States has 10 to 15 years in human DNA molecules in about 30 billion for all nucleotide sequence of determination.
Secondary structure in 1953, Watson and Crick (Watson) Crick (.) the basic structure of DNA double helix fiber structure, then this is recognized by scientists model, and the explanation for replication, and other important transcription process of life. For the further research, humidity and base sequences that etc, DNA double helix can have many types, mainly divided into A and B and Z three categories.
Generally, the closest to the cell B configuration of DNA double helix conformation, it is very similar to model. DNA and RNA molecule - the double helix area and the formation of transcription DNA molecule hybridization RNA conformation close -. Z - DNA to nucleotide dimers for unit, the Lord left to wound is serrated (Z) chain, the name. This configuration for a nucleotide chain of purine cytosine alternate area. In 1989, the American scientists scanning tunneling microscopy method directly observed double-helix DNA double-helix DNA in 1952, Austria, African American biochemist captains E.c hargaff gadamer check (1905 -), the four determination of DNA base, the content of fat poison and found adenocarcinoma of the number of thymine bases, bird whisper fat with equal the number of cytosine. This makes Watson and crick immediately thought of four bases exist between two corresponding relationship, formed the glands and thymine * matching belt whisper, birds and cytosine matching belt whisper.
The primary structure of DNA level structure is the base sequence. Gene is a segment of DNA genetic information storage, gene in its base in sequence. 1975 American gilbert W.G (UK) and the sanger ilbert F.S (anger) founded the DNA level structure of rapid determination methods, 1980 year of their chemistry prize. Since then, and constantly improve measurement method, the primary structure of DNA has many established. If people mitochondrial DNA contains a ring that 16569, lambda phage DNA contains a base pairs, rice 48502 134525 containing a base pairs chloroplasts genome, tobacco chloroplasts genome contains 155844 a base pairs, etc. Now, the United States has 10 to 15 years in human DNA molecules in about 30 billion for all nucleotide sequence of determination.
Secondary structure in 1953, Watson and Crick (Watson) Crick (.) the basic structure of DNA double helix fiber structure, then this is recognized by scientists model, and the explanation for replication, and other important transcription process of life. For the further research, humidity and base sequences that etc, DNA double helix can have many types, mainly divided into A and B and Z three categories.
Generally, the closest to the cell B configuration of DNA double helix conformation, it is very similar to model. DNA and RNA molecule - the double helix area and the formation of transcription DNA molecule hybridization RNA conformation close -. Z - DNA to nucleotide dimers for unit, the Lord left to wound is serrated (Z) chain, the name. This configuration for a nucleotide chain of purine cytosine alternate area. In 1989, the American scientists scanning tunneling microscopy method directly observed double-helix DNA double-helix DNA in 1952, Austria, African American biochemist captains E.c hargaff gadamer check (1905 -), the four determination of DNA base, the content of fat poison and found adenocarcinoma of the number of thymine bases, bird whisper fat with equal the number of cytosine. This makes Watson and crick immediately thought of four bases exist between two corresponding relationship, formed the glands and thymine * matching belt whisper, birds and cytosine matching belt whisper.
2008年10月15日星期三
Unlock the secrets of DNA
When you find that the correlation between genes and DNA, people still want to know how the DNA of a thing, it is through the life of any specific measures of so much information to the new replacement?
First people wanting to know what is composed of DNA, human being dug this love always. Levin is A result of scientists through research, the discovery of DNA consists of four more small things, the four things always name nucleotide, like four brothers, they are surname, but the name but nucleotide, were different adenine (A) and guanine (G), cytosine (C) and thymine bases (T) and the four name written, but just remember to DNA consists of four nucleotide just get together, and their mutual connections without any rule, but later nucleotide, and their mutual combinations of the great mystery. Also change.
Now, people have basically learned how genetic. The 20th century biology research findings: the body is made up of cells, and the cytoplasm and cell nuclei by membranes, etc. Known in the nucleus has a substance called chromosomes, it mainly consists of some called deoxyribonucleic acid (DNA) substances.
Biological genetic material exists in all cells, the substance called the nucleic acid. The nucleic acid polymer. By the nucleotides Each nucleotide acid, DNA and the bases. There are five bases adenine, respectively (A) and guanine (G), cytosine (C), thiamine (T) and uracil (U). Each nucleotide bases containing the only one of the five.
A single nucleotide by a chain, two nucleotides chain according to certain sequence, then twisted MaHua "into", they constitute deoxyribonucleic acid (DNA) of the molecular structure. In the structure of every three bases can form a genetic code ", and a "DNA as the base of, so every DNA is a big genetic code hidden within the genetic information beyond number, DNA molecules that existed in the nucleus chromosome. They will be as cell division transfer the genetic code.
Genetic traits of code to pass by. People about 25,000 genes, and every gene is determined by the password. People in the same genes, and both have different parts. Different parts of the difference between decided that the diversity of people. Human DNA genetic code, 30 billion of about 25,000 genes
First people wanting to know what is composed of DNA, human being dug this love always. Levin is A result of scientists through research, the discovery of DNA consists of four more small things, the four things always name nucleotide, like four brothers, they are surname, but the name but nucleotide, were different adenine (A) and guanine (G), cytosine (C) and thymine bases (T) and the four name written, but just remember to DNA consists of four nucleotide just get together, and their mutual connections without any rule, but later nucleotide, and their mutual combinations of the great mystery. Also change.
Now, people have basically learned how genetic. The 20th century biology research findings: the body is made up of cells, and the cytoplasm and cell nuclei by membranes, etc. Known in the nucleus has a substance called chromosomes, it mainly consists of some called deoxyribonucleic acid (DNA) substances.
Biological genetic material exists in all cells, the substance called the nucleic acid. The nucleic acid polymer. By the nucleotides Each nucleotide acid, DNA and the bases. There are five bases adenine, respectively (A) and guanine (G), cytosine (C), thiamine (T) and uracil (U). Each nucleotide bases containing the only one of the five.
A single nucleotide by a chain, two nucleotides chain according to certain sequence, then twisted MaHua "into", they constitute deoxyribonucleic acid (DNA) of the molecular structure. In the structure of every three bases can form a genetic code ", and a "DNA as the base of, so every DNA is a big genetic code hidden within the genetic information beyond number, DNA molecules that existed in the nucleus chromosome. They will be as cell division transfer the genetic code.
Genetic traits of code to pass by. People about 25,000 genes, and every gene is determined by the password. People in the same genes, and both have different parts. Different parts of the difference between decided that the diversity of people. Human DNA genetic code, 30 billion of about 25,000 genes
2008年10月11日星期六
DNA characteristics
A: the DNA consists of deoxidizing nucleotides of polymerization monomer polymers.
B: the DNA of deoxidizing every single nucleotide called a deoxidization nucleotide is composed of three parts: a molecule contain nitrogen base + a molecular five carbon (a) deoxyribose molecular phosphate, and DNA consists of C, H and O N, P, consisting of five elements.
C: the DNA containing nitrogen base can be divided into four categories: Guanine (Guanine Thymine (), thiamine (Adenine), Adenine, Cytosine) (Cytosine)
D: the DNA of four nitrogen-bearing bases with species. Four bases that contain nitrogen in the proportion between individuals with different species are consistent, but in different between species have differences.
E: the DNA of four nitrogen-bearing bases with strange regularity, the proportion of each in an organism's DNA in A (adenine deoxidization nucleotide) = T (thiamine (nucleotide) C (cytosine deoxidization nucleotide) = G (guanine deoxidization nucleotide). A and T between two hydrogen, C in between three and G. Hydrogen
B: the DNA of deoxidizing every single nucleotide called a deoxidization nucleotide is composed of three parts: a molecule contain nitrogen base + a molecular five carbon (a) deoxyribose molecular phosphate, and DNA consists of C, H and O N, P, consisting of five elements.
C: the DNA containing nitrogen base can be divided into four categories: Guanine (Guanine Thymine (), thiamine (Adenine), Adenine, Cytosine) (Cytosine)
D: the DNA of four nitrogen-bearing bases with species. Four bases that contain nitrogen in the proportion between individuals with different species are consistent, but in different between species have differences.
E: the DNA of four nitrogen-bearing bases with strange regularity, the proportion of each in an organism's DNA in A (adenine deoxidization nucleotide) = T (thiamine (nucleotide) C (cytosine deoxidization nucleotide) = G (guanine deoxidization nucleotide). A and T between two hydrogen, C in between three and G. Hydrogen
Deoxyribonucleic acid
Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. The main role of DNA is the lon-term storage of information and it is often compared to a set of blueprints, since DNA contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information
2008年9月14日星期日
DNA paternity test
Identification of parent-child relations are the most use of DNA typing is identified. People's blood, hair, saliva, oral cells can be used by all paternity testing, is very convenient. A person has 23 pairs (46) chromosome, the same position on the same chromosome a gene called alleles, a general from his father and one from the mother. If a DNA test to the site of the allele, the same as a mother, father and another should be the same, otherwise there is a doubt. The use of DNA for paternity testing, as long as a few dozen to a dozen sites for DNA testing, if all the same, we can determine the parent-child relationship, if there are more than three different sites, parent-child relationship can be ruled out, there are 12-bit Different point, it should consider the possibility of gene mutations, and do some testing sites to identify. DNA paternity testing, the negative parent-child relationship of nearly 100 percent accuracy rate, certainly the accuracy of the parent-child relationship can be reached 99.99 percent. DNA paternity test test FAQ What is a DNA paternity test test » DNA (deoxyribonucleic acid) is the physical body of the atomic material. Each atom has 46 chromosomes, while men and women of the sperm cells and eggs, and each has 23 chromosomes, when the sperm and egg combination of time. This 46 atoms to create a life on the chromosome, each from a father who inherited half of the material elements, while the other half from the mother was. DNA paternity testing testing with the traditional blood tests are quite different. It can be in different tests on the samples, including blood, gills cavity cell, tissue samples and semen samples. Because blood type, such as Type A, B-, O-or-RH, the crowd in the use of more common, used to identify each individual's blood relationship, but as DNA paternity testing testing effective. In addition to the real twins, each person's DNA is unique. Because it is so unique, like fingerprints, for paternity testing, DNA is the most effective method. We are usually the result than the requirements of the court also accurate from 10 to 100 times.
DNA replacement
Gene therapy is integrated with the normal gene into the cells, to correction and replacement of a disease gene therapy. Currently in broad terms, some will be transferred to the genetic material of cells, in its role to achieve the objective method of treatment of disease, but also that of gene therapy. At present gene therapy, the method used can basically be divided into the following: 1 DNA Correction DNA correction that will be linked pathogenic DNA base pairs to correct the anomaly, and normal part be retained. 2. DNA replacement DNA replacement is to use the normal DNA in DNA by homologous recombination, in situ lesions replacement cells pathogen DNA, the DNA within the cell to fully return to normal conditions. 3. The addition of DNA DNA will be added to that purpose DNA into cells or other cell disease, removing abnormal DNA, but through DNA purpose of the non-targeting, the expression of compensation to the function of DNA defects or the original function has been strengthened. At present DNA for use of such methods. This approach is the addition of the more dominant DNA for the treatment of recessive disease. 4. DNA inactivation Early generally refers to anti-sense DNA technology. It is the specific anti-RNA, including antisense RNA, antisense and ribozymes DNA into cells, transcription and translation in blocking the abnormal expression of certain genes. In recent years another anti-gene strategy, peptide nucleic acid, DNA and RNA interference removal. [DNA is the genetic material of all biological basis: DNA (deoxyribonucleic acid) is a class of nucleic acid, the molecule contains deoxyribose named. DNA molecules very large (at least in general molecular weight over 1 million), the main component is deoxynucleotidyl adenine, guanine deoxynucleotidyl, thymine and cytosine deoxynucleotidyl deoxynucleotidyl. DNA exists in the nucleus, mitochondria, chloroplasts, can also be free to exist in some state of the cell cytoplasm. Most of the known phage, part of a small number of plant and animal virus also contain the virus in the DNA. In addition to RNA (ribonucleic acid) and the phage, DNA is the genetic material of all biological basis. Parent-child organisms and the similarity between the so-called inheritance of genetic information, are stored in the DNA molecule. 1953,詹姆斯沃森and Francis Crick describe the structure of DNA: from one-to-many linked nucleotide composition of each other coiled double helix. They and London's National Institute of Technology physicist Frederick Ke Wei Er Jinsi shared the 1962 Nobel Prize in Physiology or Medicine. [Obesity gene -- The Royal London Hospital scientists found that obesity in the body, there is a unique function of the gene, the gene of the three members of the body of the chromosome. As the obesity gene existed only in the body, so scientists call it "fat gene." The study found that obesity gene can promote the body to create a transport fat in the blood protein - "APO-D" gene. The gene, the more fat the more fluent of blood transmission, the accumulation of body fat also the more people will be obese. Below scientists did an interesting experiment: Let a pair of carrying the obesity gene mice mating, the results of each roll and future generations of wandering round melon, which is tantamount to meat ball, and did not allow a mouse obesity gene for mating, birth The less fat in mice, each are very thin. Genetic scientists in accordance with this model, can also produce the body of fat at 20 to 50 percent of the Feishou different degrees of mice. Further found that the genetic obesity and the situation is slightly different from rodents, a generational genetic. That is, people can observe, in a considerable number of families, fat grandmother would not normally be obese gene passed on to their children, but passed on to her grandchildren. Scientists also found that obesity-related genes more than one. For example, New York, a Rockefeller University research team recently announced that they After eight years of long study, found that a control appetite and energy metabolism genes. It is said that this gene can be sent to the brain to stop eating a signal to the brain so that the masters of timely weakening appetite, in order to avoid excess energy if the gene variation, the owner will be increased appetite, Tanzui eat, and eventually become A big fat man. Further research revealed that the gene from the 4500 base component, part of which can produce from 167 amino acids of the protein. If this normal protein synthesis, will be sent to the brain's signal to stop eating if the protein coding the amino acid composition of coding the first 105 amino acid residues of the unusual base, the signal will stop eating failure, leading to obesity.
dna
Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. The main role of DNA is the lon-term storage of information and it is often compared to a set of blueprints, since DNA contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information
DNA is the carrier of genetic information
DNA is the carrier of genetic information, the parent must take their own DNA molecule as a template accurate reproduction into two copies, and assigned to the two daughter cells, go to complete its mission of the carrier of genetic information. And the double-stranded DNA structure of this type of genetic material for the maintenance of the stability and the accuracy of reproduction are extremely important. (A) DNA copy of the semi-reservation Click Waston and raised in the DNA double helix structure on the model of DNA replication during the process of the study, they speculate, DNA base pairs in the process of copying the hydrogen bonds between the first fracture, double helix of the Rotary separately, were linked to each template Synthesis of the new chain, each offspring of a DNA chain from the pro-generation, and the other is a new synthesis, so as to retain a half-copy (semiconservative replication). (B) DNA replication 1. DNA double helix of the rotation (1) single chain DNA-binding protein (single-stranded DNA binding protein, ssbDNA protein) (2) DNA helicase (DNA helicase) (3) DNA of the chain 2. Okazaki fragments and a half does not copy a row 3. Copy the trigger and termination (C) telomeres and telomerase 1941-American Indians McClintock (Mc Clintock) raised a telomere (telomere) of the hypothesis that the chromosome ends must exist a special structure - the telomere. Telomere now known at least two roles: ① chromosome end protection from damage to chromosomes remained stable; ② and nuclear fiber-connected so that the chromosome can be targeted. [DNA of the physical and chemical properties -- [Edit this paragraph] DNA is macromolecular polymers, DNA solution for the polymer solution, with very high viscosity. DNA on the role of ultraviolet radiation is absorbed, when the nucleic acid degeneration, the absorption value increased when the degeneration of the nucleic acid can be complex, absorption values will be restored to the original level. Temperature, organic solvents, acidity, urea, amide, and other reagents DNA molecules can cause degeneration, even in the DNA double bond between the hydrogen bond breaking double helix structure untied. DNA (deoxyribonucleic acid) that DNA (genes and chromosomes an integral part of) deoxynucleotidyl the polymer, is the major components of chromosomes. The vast majority of genetic information stored in the DNA molecule. [Distribution and function -- [Edit this paragraph] Prokaryotic cell chromosome is a long DNA molecule. Eukaryotic cells in more than one chromosome, each chromosome containing only a DNA molecule. But their general than the original cells in the DNA molecule and protein and the combination. DNA molecule's function is the storage of all species decision RNA structure of the protein and all the genetic information; orderly planning of cells and tissue components of the time and space; identified throughout the life cycle of biological activity and identify biological personality. In addition to chromosomal DNA, a very small amount of the different structure of DNA found in eukaryotic cells in the mitochondria and chloroplasts. DNA of the virus genetic material is DNA. [The discovery of DNA -- [Edit this paragraph] Since the genetic Mendel's law was re-discovered, the people also raised a question: genetic factor is not a material entity » In order to solve the problem of what is, people began to DNA and protein research. As early as 1868, people have discovered DNA. German chemist in the laboratory Huopei Siler, a Swiss post-graduate名叫米歇尔(1844 - 1895), his lab near a hospital threw the bandage with a sense of Nongxue Interest, because he knows that those Nongxue to defend human health, germs and "combat" and died in the WBC and was killed in human cells, "body." So he carefully the bandage on the Nongxue collected and used pepsin decomposition, and found the bodies of most of the cell decomposition, but the nuclear non-functional. He further material within the nucleus of an analysis and found that cells containing a phosphorus and nitrogen-rich material. Huopei Siler experiments with yeast, that the nucleus Michel substances found to be correct. So he would give such a separation from the nucleus of the material named "nuclide", and later it was discovered that it was acidic, so to call "DNA." From then on the people of nucleic acid carried out a series of fruitful research. The early 20th century, Germany Ke Saier (1853 - 1927) and two of his students Jones (1865 - 1935) and Levin (1869 - 1940) study, understand the basic chemical structure of nucleic acid, that it Nucleotide is composed of many macromolecules. Nucleotide base pairs from, ribose and phosphate posed. Of which there are four kinds of bases (gland Piao Yin, the birds allopurinol-Yin, thymine and cytosine), there are two ribose (ribose, deoxyribose), the DNA into RNA (RNA) and deoxyribonucleic acid (DNA) . Levin eager to present his research results, the misconception that four kinds of bases in DNA, are equivalent to the volume, which is derived from the basic structure of DNA by four with different nucleotide base pairs of connecting the four-nucleoside Acid, as the basis for a nucleic acid polymer, proposed a "four nucleotide hypothesis." This hypothesis wrong, the understanding of the complex structure of nucleic acids from the considerable obstacles, also, to a certain extent, affected the people's understanding of the function of DNA. It was felt that although the DNA structure exists in the important - the nucleus, but its structure is too simple, it is difficult to envisage it in the process of genetic what role. Protein than the discovery of DNA as early as 30, have developed rapidly. The beginning of the 20th century, composed of 20 kinds of protein has 12 kinds of amino acids were found to 1940, all were found. 1902, a German chemist for Xie Erti between amino acid peptide chain connected to the formation of protein theory, in 1917 he was synthesized by the glycine 15 leucine and three of the 18 components of long-chain peptide . Thus, some scientists envisaged, it's likely that the genetic protein plays a major role. If the participation of genetic DNA, and protein is also bound together the nucleoprotein at work. Therefore, when biological protein is generally inclined to think that the carrier of genetic information. 1928, U.S. scientists Griffith (1877 - 1941) have used a capsule, and a toxic-free capsule, toxic weak Streptococcus pneumoniae experiments on rats. He used a high temperature to kill bacteria pod after pod with no live bacteria inject people with mice, rats and he soon found that the incidence death, and he's in the blood of rats from isolated the bacteria live in a pod. This shows that even without passing bacteria from the dead of a pod of what was in the material, so that no dioxin into a pod of bacteria. This assumption is correct? » Griffith also in the test tube experiments and found to have died in the U.S. with live bacteria without passing on the bacteria at the same time in test-tube culture, without passing all of a pod into a bacteria, and found that no pod of long Protein to dioxins is dead in a pod of shell left over from the nucleic acid (as in the heating, dioxin in the nucleic acid has not been damaged). Griffith said the DNA for "transforming factor." 1944, the United States Xijunxuejia Avery (1877 - 1955) from the United States have isolated the activity of the "conversion factor", and this kind of material to the test whether there is the protein test results were negative, and proved "Conversion factor" is the DNA. However, this discovery has not been widely recognized, people suspected of technology at that time can not be a net addition of protein, a protein residue into the role. American scientists德尔布吕克Germany (1906 - 1981) of the phage group firmly believe that the discovery of Avery inalienable. Because they are under the electron microscope to observe the shape of the phage into E. coli and the growth process. Phage bacterial cell is a host for the virus, individual and small, with only electron microscope to see it. It is like a small tadpole, the external is composed of protein from the first film and the tail sheath, the head of the internal containing DNA, on the tail end of silk sheath, the substrate and small hook. When the phage infection Escherichia coli, the first扎in the tail end of the cell membrane of bacteria, then it would inject all of the DNA in human cells to the bacteria, protein shell of bacteria cells remain on the outside, no longer what role the . After the bacteria enter the cells of the phage DNA, the use of bacterial material and rapid synthesis of DNA and protein phage, which many copy and the original shape of the same size phage new phage, until the bacteria was completely disintegrated, these phage did not leave the dead bacteria , Go the other bacterial infection. In 1952, key members of phage dna group Heer Xi (1908) and his students Chase isotope tag with advanced technology, do phage infection of the E. coli experiments. He E. coli T2 phage DNA markers on 32 P, protein shell markings on the 35 S. To use the T2 tag phage infection of the E. coli, and then be separated, the phage will be marked with 35 S shell to stay outside in E. coli, only within a 32 P phage DNA markers were all Note Escherichia coli, E. coli, and Phage the successful conduct of breeding. This experiment proved that a DNA transfer of genetic information, which is the protein from the DNA of the directive. This result was immediately accepted by the academic community. Almost at the same time, Austria biochemists Chargaff (1905 -) in the four kinds of nucleic acid bases in the re-determination have been fruitful. In Avery's work under the influence, he considered that if the different species is due to the different DNA, the DNA structure must be very complicated, or difficult to adapt to biological diversity. Therefore, he set out on the text of the "four nucleotide hypothesis" had a doubt.dna dna dna dna dna
Deoxyribonucleic acid
Deoxyribonucleic acid (DNA, for the acronym in English Deoxyribonucleic acid), also known as DNA, chromosome is the main chemical constituents, but also of genetic material. Sometimes referred to as "genetic particles," because during the breeding process, the father of the generation part of their own DNA copy delivered to offspring, thus completing the spread of characters. a. DNA is a nucleic acid from the monomer polymerization from the polymer. b. DNA from each composed of three parts: part of the five members of nitrogenous base + carbon sugar (deoxyribose) + member of phosphate. c. The nitrogen-containing nucleic acid bases can be divided into four categories: guanine (G), thymine (T), adenine (A), cytosine (C) d. DNA base pairs of four nitrogen-containing components of species-specific. That is, the ratio of four nitrogen-containing bases in the same species, different individuals is the same, but again there are different species differences. e. DNA base pairs of four nitrogen ratio is peculiar laws, and every kind of DNA in the organism A ≈ TC ≈ G Jia Kafu law. Discovery of DNA Michel called nucleic acid is a young Swiss chemist discovered, it's still 1869, to 1909, a U.S. biochemist also found that DNA in the two ribose molecule carbohydrates, nucleic acids also have two , Called a deoxyribose acid, is the English abbreviation for DNA, the other is RNA, the initials are RNA. DNA in the nuclei in general only, and RNA in the nucleus in addition to Chinese and foreign, also located in the cytoplasm. Xijunxuejia Avery pneumococcal transformation through research, the accidental discovery of the DNA, is that many people were looking for a long time the genetic material. In the DNA, the genetic secrets of life with the genetic material, so, in the end decide what is to explore the phenomenon of genetic life, and finally to the open secret of the time, at this time is the 1940s. Untie the secret DNA When the gene is found DNA, people still like to know how this DNA is a kind of things, it is also what specific approach to the lives of so many information to the new successor does » First of all people want to know what DNA is composed of human love is always asked at the end of this shaver. The results have a called Levin of scientists through research, found that DNA from four of the smaller things, these four things name is the total nucleotide, like four brothers, all of them named nucleotide, But names are different, are adenine (A), guanine (G), cytosine (C) and thymine (T), the four names to remember, but remember that as long as the DNA is from four Nucleotide only casually together, and they have no connection to each other laws, but later nucleotides in fact not the same, and their mutual combination of the ever-changing methods of great mystery. Even a single nucleotide into a chain, linked by two nucleotide a certain order, and then twisted into a "Serratula" kind, a deoxyribonucleic acid (DNA) of the molecular structure. In this structure, every three bases can form a genetic "password" and a DNA base pairs on as many as several million, so each DNA is a significant genetic code books, the inside of the genetic information In countless more, this DNA molecule found in the nucleus on the chromosome. They will pass with cell division genetic code.
genetic level above 99 percent is the same
Any two people at the genetic level above 99 percent is the same, only a small part of the genome sequences vary from person to person. Understand these differences can help us understand human disease susceptibility, and environmental factors on drug response of the different. "Genomics Research Institute in Shenzhen, Dr. Ye Jia accept the" scientific Times "told reporters. In recent years, a large number of epidemiological investigation and study results showed that the incidence of certain diseases in the existence of significant differences among different races. If the incidence of hypertension in white for 5% to 7%, while in blacks could be as high as 20 percent to 30 percent, the lowest yellow people. China's different ethnic groups among the incidence of hypertension there are also significant differences. However, this difference is come from » Study found that the genome of different people at least 99.99 percent of the base pairs are the same, only less than 0.01 percent of the existence of differences. However, this is called "single nucleotide polymorphisms" the DNA bases on a single chain of change, not only the people decide whether or not susceptible to certain diseases, but also between different races decided in height, colour and size Such as the difference. At present the relationship of these scientists also know little about. April 14, 2003, from the United States, Britain, Japan, France, Germany and Chinese scientists to participate in the six countries, known as "life sciences landing program," The Human Genome Project, completed by the 3 billion base pairs of The key to the human genome sequence of DNA sequencing work plan. CAS academicians, the National Human Genome Research Center of the South Executive Director, said researcher Zhao Ping, has completed the human genome (sequence) from different ethnic origin of the five individual, is a reference atlas. In order to health and medical applications, the scientific community must recognize different types of people in the sequence between the differences and these differences in health and disease and the mutual relations, until the last to understand these differences to the table of the mechanism. Mr Jia said with emotion: "2007, sequencing technology was a great breakthrough in sequencing capacity as a hundredfold increase, the cost of sequencing a hundredfold fall. DNA Father James Watson, genomics pioneer J. Craig Venter personal genome And 'Yanhuang on the 1st,' the first Chinese person has complete genome. These are carried out for 1,000 genome project laid the foundation. " Goals: a high-precision genetic variation map The current human genetic variation data, such as the human genome haplotype map (HapMap), has been confirmed that the value of human genetic research. Haplotype map and the use of relevant data, scientists have discovered more than 100 common diseases associated with the human genome region. However, due to the existing patterns of fine is not enough, researchers often need to both expensive and time-consuming DNA sequencing to further precision to find disease genes and their variability. Genome project through the 1,000-painted on the new map will allow researchers to more quickly identified and disease-related gene mutation, thereby able to use such genetic information more quickly develop common disease diagnosis, treatment and prevention of new Strategy. "It aims to end a very high accuracy and cover nearly all of the genome map of genetic variation, to provide the basis of human genetic variation information for the study of human-specific diseases." Mr Jia said. The so-called 1,000 genome project is not only sequenced the genome of 1,000 individuals, but to sequence more than 1,000 personal genome. The first is his personal genome sequenced the entire genome to understand the situation and then proceed to a large number of individual genome comparative analysis. According to Jia Ye, 1,000 genome project's first phase will take about one year, three experimental pilot projects that the results will be used to determine how efficient and cost-effectively drawing this map of human genetic differences. The first pilot project will include two experimental nuclear families (parents and a grown-up children) the whole genome sequencing depth of each genome sequencing, the average depth is 20 times that of repeated 20 times. This six individual generated by comprehensive and detailed data sets, this plan will help determine how to use new sequencing platform to identify genetic variation. This is both a personal genome on a method of exploration, will also serve as the whole scheme of other projects to compare the foundation. The second pilot experiment project will conduct 180 individual shallow sequencing of each genome is twice the average depth. This will be used to test new sequencing technology LIGHT sequencing data for detection and location of the sequence variation capacity. The third project will pilot test of the 1000 Personal 1000 coding regions (also called exons) of the sequence, its purpose is to explore how better to be about 2 percent of the genome of protein coding genes of a more detailed map. 1,000 Genome Project sequencing work will be Britain's Sanger Institute, China's Shenzhen, Genomics Research Institute, and including the Broad Institute, Washington University School of Medicine Genome Sequencing Center and Baylor College of Human Genome Sequencing Center, U.S. Human Genome Research Institute (NHGRI) of large-scale sequencing platform shared. Mr Jia said: "This is a project of international cooperation, Shenzhen, Genomics Research Institute as a major commitment to one of the existing cooperation in information systems unit of the State Engineering Research Center of Chinese Academy of Sciences and the Beijing Genome Institute, hope to have An increasing number of research institutions in. " Means: low-cost efficient sequencing technology 1990, the U.S. Congress formally approved the Human Genome Project. The human genome project took 13 years and cost about 3 billion U.S. dollars, during which a total of six of the 16 national laboratories more than about 1,100 biologists and computer experts involved in the human history of the largest scientific research. "1,000 genome project so ambitious project two years ago is not imagination, are now able to start due to sequencing technology, bioinformatics and genomics groups such as the development of disciplines and technological progress." Mr Jia said. Mr Jia told reporters that "Yanhuang No. 1" in the work of overcoming a lot of technical problems, and accumulated a lot of experience and methods. For example, the completion of "Yanhuang 1" Genome Sequencing the time, Chinese scientists and a good grasp on the application of the genome as a personal basis of the next generation of sequencing technology and the establishment of a large number of follow-up analysis, the splicing method, all For 1,000 genome project has laid a good foundation. Although the sequencing technology and a significant reduction in cost, but sequencing a genome or individual pieces of a very extravagant things. May 31, 2007, the Nobel laureate, known as "DNA of the father" of the United States become a world famous scientist詹姆斯沃森first solo version of the genome owner, but the cost of up to 2 million U.S. dollars. Watson completed DNA sequencing work of the United States 454 life sciences companies Jonathan Rothberg, founder and president, said: "We are in a 10,000 U.S. dollars gene map forward, will soon be reduced to 1,000 U.S. dollars." Genome project will be 1,000 Use of several new high-throughput sequencing platform, through the establishment of more efficient and lower-priced new sequencing technology, the plan will ultimately cost could be reduced to 30-50 million U.S. dollars, time shortened to three years. Mr Jia also said: "Although a great breakthroughs in science and technology, but sequencing a person's genome will be temporarily in the cost of 10 million yuan on. Hope in the near future, with the sequencing of the lower cost, work Constantly improve the speed, each of us can get our own genome, as we go to the hospital for an X-ray inspection as easy. " In co-sponsor and participate in the international genome project of 1,000 at the same time, Shenzhen, Genomics Institute of China also initiated the "Yanhuang plan" so that a wider study of the Chinese population genetic variation, high-resolution mapping of the Chinese people Patterns of genetic variation. Published in the first of China's high-quality genome - "Yanhuang 1", launched the second phase of the "Yanhuang 99" plan, the study will be 99 individual Chinese people to genome sequencing and polymorphism Comparison. Shenzhen, Genomics Research Institute to participate in 1,000 Genome Project completed the sequencing Chinese samples will serve as "Yanhuang" part.
HBV-DNA
DNA is deoxyribonucleic acid, the virus is relying on DNA copy of the copy to complete, DNA showed that the higher the concentration of virus replication drug more active, HBV-DNA HBV infection is the most direct, specific and highly sensitive indicators, HBV - DNA positive, suggesting that HBV replication and infectious. HBV-DNA replication Unlike a real organism, the virus is not split by the growth and reproduction, including their own, but we like casting machine parts, according to a copy out of the mold. Virus DNA contains a number of procedures to guide the virus genetic material and other structural components of proliferation. In addition, the viral DNA also contains some information to make a single component with the help of cytokines, spontaneous assembly into a new virus particles. In medicine, the propagation of the virus known as the "copy", in the process of reproduction, there are two very important factors: One is the catalyst, and the other is a template. Without these two factors, hepatitis B virus can not reproduce. Hepatitis B virus replication "catalyst" is the hepatitis B virus DNA (that is, HBV-DNA) polymerase. This polymerase not the role of hepatitis B virus replication will stop. Hepatitis B virus genome (HBV-DNA) by two spiral of DNA chain surrounded a ring structure. One of which has been linked with negative longer a complete ring and another one is the shorter length of chain, a semi-circular. Infected cells in the liver, this semi-ring of DNA strands will be linked to negative as a template, the catalyst ─ ─ HBV-DNA polymerase to extend the role of the ultimate form a complete ring. At that moment, the hepatitis B virus genome to form a complete ring of the double-stranded DNA. We have this DNA called covalent closed circular DNA (that is, cccDNA), it can be seen as a virus replication of the original template. Template form, the virus genes to one of a cccDNA as a template, the use of liver cell gene in the DNA polymerase enzymes and the "catalyst", a section of a section of genes and gene copy, a negative chain and are linked. And then assemble together to form a new HBV-DNA particles. HBV-DNA normal Usually less than 10 of the three power, the conclusion was negative, the report write negative, or "<10 3 power." HBV-DNA examination is very sensitive, changes in the same order of magnitude that the virus can not normally change, for example, 2 X10 5 and 5 X10 power of the five power is not very likely to change, but the five-power 2 X10 and 2 X10 power of the four, there is Changed. It is worth noting that, HBV-DNA-positive hepatitis B carriers may not require treatment, but also with aminotransferase (ALT) level. In general, only when aminotransferase 2 times greater than normal when they should be given treatment; HBV-DNA value of the number of liver damage and the extent there is no direct relationship. Da Sanyang carriers of hepatitis B HBV-DNA higher than normal, but severe liver damage may not be, because hepatitis B virus itself does not directly harm the liver cells
DNA sequence
In molecular biology research, DNA sequence analysis is further research and the basis of the target gene. At present the technology for sequencing, and other major Sanger (1977) invented the end-mediated chain termination method and Maxam and Gilbert (1977) invented the chemical degradation method. This two kinds of methods in principle, very different, but are based on the nucleotide in a fixed point, random in a particular base at the end, a A, T, C, G four different length of the A series of nucleotides, and then urea degeneration PAGE gel electrophoresis test to obtain DNA sequence. Currently Sanger sequencing method has been widely used. Sanger sequencing method is the principle of using a combination of DNA polymerase to extend the template sequence to be determined on the primer. Until the introduction of a chain of nucleotides termination. Each time a sequence of four separate from the reaction composition, each containing all four reaction deoxynucleotidyl triphosphate (dNTP), and mixed with a limited number of different dideoxy nucleoside triphosphate (ddNTP) . As ddNTP lack of extension of the required 3 - OH group, to extend the oligonucleotide selective in G, A, T, C or terminated. Termination points from the corresponding reaction dideoxy on. Each of dNTPs ddNTPs and the relative concentration can be adjusted so that the reaction of several hundred to several thousand head of a base linked to terminate the product. They have a common starting point, but terminated in different nucleotide, through high-resolution degeneration gel electrophoresis separation of fragments of different sizes, the gel can be used after X-ray film Autoradiography or non-isotopic tags Jin
PCR technology
PCR technology with a high degree of specificity, selectivity, sensitivity, and fast, simple and easy automation, in clinical work in wide attention and reasonable application. At present in many of our primary health care units have been carried out PCR application of the research. PCR technology is very simple, very clear principle, conditional units can be implemented more smoothly, but after all PCR technique is a new thing, subject to many conditions factors, it is not easy to do better. PCR technology applications in the encounter in the course of this or that issue, even more will be completed with the fact that the opposite result. To enable us to smoothly carry out PCR work, and better tools to play the role of PCR technology, we work under the PCR years of lessons learned, the PCR amplification process of some of the problems often appear with a brief summary, available to the general scientific research Workers as a reference, Paozhuanyinyu, welcomed the inadequacy of the correction. A false positive amplification Sometimes in the course of the experiment will be met by all the samples tested positive, and electrophoresis of PCR products with uniform brightness, which is amplified when the system is polluted the most typical of a performance, need to carefully inspect and remove sources of pollution, the general should be Start the following steps: ⒈ reagents pollution: Reagents provided by the manufacturer or a component in the factory or the transport, storage process of being contaminated. Detection method can be reagent kit brochures will be installed at a direct place in the PCR-amplified (without the negative control, and adequate distilled water), will be simple and effective reagent to judge whether the contamination. ⒉ laboratory contamination: This is the most common sources of pollution, because of PCR technology in a few hours in the template will be some specific amplification to the millions of times more likely to result in the expansion of mandrax electrophoresis process of pollution, such as pipettes, console With the evaporation or by the formation of aerosol pollution and the whole laboratory. Amplified products is the most effective templates, once the pollution of their pollution levels are more serious. Judgement: the experiment could be the most crucial steps such as packaging reagents, sample processing transfer to a new environment or transferred to the ultra-clean work Taichung completed. Of course, the use of pipettes, Tsui suction tube (centrifuge tube) should be completely replaced. Solution: laboratory contamination of PCR is the most vulnerable in the course of the phenomenon, but once the pollution, eliminate sources of pollution also extremely difficult, often takes the entire laboratory and experimental equipment cleaned thoroughly dealt with, so it should be a prevention-oriented, experimental In strict compliance with the basic requirements of sample processing and amplification and electrophoresis product should be separated as much as possible, preferably in two rooms. Amplified by the pre-treatment with pipettes and after the sample was amplified by the Pipettes should be strictly separated, not interchangeable. PCR room should maintain good ventilation, cleaning, preferably exclusive. ⒊ pollution sampling: In the course of the experiment, and sometimes there will be a number of positive results of the high rate, and a number of positive results and rate of decline in many, so repeatedly, a phenomenon largely because of pollution caused by sampling, and generally speaking the formal reagent manufacturer, its agent The factory to go through strict quality inspection, grant, award, in particular the differences are very small, so obviously there will not be repeated, this phenomenon was mainly due to the collection of samples or suction tube caused by pollution. PCR amplification is very sensitive, and general laboratory test tube by the repeated use of the injection can not be washed way to remove trace DNA, trace DNA of these will become PCR template, a positive PCR result, the degree of contamination sample test tube Different, so there Mandrax Mandrax high-low phenomenon solutions recommended a suction tube and Tsui sampling. Second, the false negative amplification: If successive negative results are amplified, or known positive samples appear negative PCR result, the general view that this is false negative, there is this phenomenon for several reasons: ⒈ equipment failures: A full-Yam results, first of all to consider whether the normal operation of equipment. Correct judgement of the equipment working conditions, ruled out false negative is the basis for other reasons, the equipment is functioning properly PCR amplification Buju one of the most crucial. Judgement see if the equipment is normal, we must first of heating temperature of the accuracy of the volatility of the Chinese request, the difference between whether the hole to meet the requirements, PCR amplification of equipment are often heated and the temperature difference between the requirements of a high Accuracy, if too much error, it is bound to arise false negative. It should be noted that the letter can not be famous, we often found that some brand-name machines temperature differences as high as second over. ⒉ reagent failure or invalid: Whether the normal understanding of machinery, the reagent can detect. We must first understand whether the agent over the period to test whether the method of storage requirements, if the kit in the period to which the storage method is correct, then they should be carefully, carefully determine whether the reagent is invalid or failure reagents reagents. The positive samples can be known, or kit provided by the positive control, expanded operations in strict accordance with a statement, and then amplified by double-distilled product diluted 1,000 times, as a template for the second time amplification, judge the results, if it is Negative note reagent is invalid or failure, if the positive results of the following methods available then determine the sensitivity of reagents. ⒊ reagent sensitivity: Sometimes the positive test for low rate, the so-called partial-positive rate is the rate that a false negative result, this phenomenon often associated with the following three factors: But the quality of reagents ① Commissioner; ② operation was not standardized; ③ subjective criteria unscientific. The reagent is correct quality and operation of these two points is relatively easy to check and a reasonable improvement. Focus to mention here: there often encounter some unscientific concept, we used to use some samples should be negative, some samples should be positive, or simply to positive rates. The concept of subjective judgement whether the reagent qualified This is a very unscientific and subjective reasoning. If the determination of serum HBV, can not be used abstract should be a positive rate of 60% or 20% of such a concept to judge, the same can not "two pairs of semi-" the result of judgement "PCR results," This is because the "two On a half "and" PCR "are two totally different detection method, the results of the significance of the difference between its medical personnel for the information provided is very different and more by the use of the" two pairs of semi-"Reagents Whether as a quality evaluation standard test yet to be determined. The world's more recognized standards for Abbott's only "two pairs of semi-" reagents, domestic "two pairs of semi-" According to the Ministry of Health reagent checks show that the pass rate was 50 percent, how can you be assessed as a quality standard? Reagents sensitivity of the evaluation criteria should use the following method of scientific evaluation, the first sample selection criteria such as HBV sequence plasmid, the standard positive serum, such as tuberculosis bacteria use the appropriate medium such as serum and sputum, and so on a limited dilution 1:10,1:100,1:1000,1:10000 so gradually raise the price of its dilution of the sensitivity of reagent is generally believed that if the serum HBV positive standards with normal serum diluted 10,000 times more, per milliliter of TB In about 100 still measured positive results, the sensitivity of the reagent is sufficient to determine the sensitivity of reagent is sufficient to determine the sensitivity of reagents be judged after the detection reagent coverage, because pathogenic micro-organisms have different type or variation Strain, qualified reagents should not be Lou Jian. Finally kits to determine the opposite sex, the general laboratory can be used by different pathogens Manual operation of the sample to determine its expansion to other pathogens, also have a positive, the specificity of the accuracy of what can be achieved, after more than three areas of Scientific research will be able to judge the quality of reagents. Third, the amplified products tailing Sometimes amplified products electrophoresis after one fluorescent Mission (Smear phenomenon), or a series of bands, these kinds of phenomena with the following major factors: ⒈ amplification system flawed: This phenomenon shows that a non-specific amplification, and a non-specific amplification and amplification system in the concentration of magnesium ions, with concentration, DNTP is closely related to the concentration required serious adjustment with a view to avoid such a phenomenon. It is also appropriate to improve the annealing temperature, thereby enhancing amplification specificity. ⒉ imperfect template approach: The principle of PCR Although very simple, but the rational application of this technology is extremely complicated, such as the PCR DNA polymerase one of the major components of the impact of many factors, what is the role of these factors in the polymerase, the mechanism so far Still unclear, so is wrong with the improper handling of samples may inhibit amplification, may also lead to non-specific amplification. General secretion samples, mainly from exfoliated cells, to avoid collecting too many Nongxing secretions, and sputum samples must fully liquefaction, and so on. ⒊ primer design unreasonable: Primer design should be guided by several principles. First, the general primer should be composed of 15-30 months BP; Second, the primer in the base should be randomly distributed, the same can not have a bunch of other bases or not a common structure; third, GC base content should be 45 -- About 55%; Fourth, the two primers in the 3 'non-identity can not be there. To which primers and gene homology between the group is a non-specific amplification of the main reasons, we generally in the design of primers, often only aware of their genome sequence in a certain period, so we must make full use of such information ingenious design To a reasonable primer, and through repeated comparison, confirmed that the final to determine its ability to detect. 4, single-product of electrophoresis and fluorescence with more general with fluorescent PCR amplification, the PCR results of the judgement the most simple way is to agarose gel electrophoresis, bromine B amylin staining, 320 nm in the UV excitation observed Fluorescent strip, if there are clear and specific amplification product will be flat in electrophoresis expected a clear position in the fluorescent-band amplification system in accordance with the standard preparation of the response, with its concentration in the 0.1-0.5 mM , The general circulation by 30 after the expansion, there is still a considerable number of free primer exists, so there is a slab electrophoresis about 20 BP (electrophoresis faster), fluorescent light with the primer, so each electrophoresis Have two Ying-zone, in front of one, each of the points have everything with the primer. Primer design very important, because a large genome DNA sequence, in addition to the specific amplification, are often very easy to produce non-specific product. If the primer with the genome of the existence of a broader identity, then there will be serious non-specific expansion of mandrax, not only with the specific primer amplification regional integration, but also a series of regional and other non-specific binding, and the choice of primers, , And often have to consider sensitive issues, especially the clinical test kit, less able to detection of pathogens to a few, we mostly used in the pathogen genome duplication in the DNA sequence design primer, if they repeat not strictly homologous , On the possible length of the amplified products and a multi-band amplification. Pathogenic variant, with the foregoing, we often use the high sensitivity of a repeat of the gene as a primer design section, in some pathogens, such as tuberculosis in the treatment process, will be a serious distortion, including its Genetic material changes in the chromosome deletion, ranging from digital exchange, such as the insertion of other sequences. If these deficiencies and a range of the exchange is in our choice of amplified sequence, will also appear different length of the amplified products, resulting in a number of amplified products with. PCR gene amplification technology simple, application of the increasingly widespread, but its impact on many factors, in the course of practice is now often this or that issue, not even the expected results, or appear unable to explain the phenomenon. It is true that a large number of scientific workers in recent years with concerted efforts, made many valuable experiences, so that this technology are maturing, after all, PCR is the only one in recent years the emergence of new technologies, many of the problems is still not very good To explain or resolve. With the letter to the PCR in-depth study, the application of the PCR process of constantly sum up experience, PCR this new technology for human development will make
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