pcr

[ "Junk DNA" -- [Edit this paragraph] Yeast and worms such as the simple biological evolution is how birds and mammals such as the complexity of this biological » Against a group of the extensive comparative studies have shown that the answer to that question may be hidden in the garbage of deoxyribonucleic acid (DNA) in. U.S. scientists have found that the more complex biological, carrying more junk DNA, and it is precisely these is not encoded the "useless" DNA to biological evolution to a higher complexity of the organism. Since the first eukaryotic organisms - ranging from yeast to human cells have the biological - the genome has been deciphered, scientists have wondered why the majority of DNA does not form a useful genes. To protect the chromosome mutation from the structure of support for the so-called junk DNA may explain the many species. But last year from humans, mice and rats to get a complete agreement on junk DNA studies have shown that in this region may contain important adjustment mechanism, which can control the basis of biochemical reactions and the development process, This will help biological evolution to a more complex organism. Compared with the simple eukaryotes, the more complex biological gene mutations do not doubt the fact that this has greatly strengthened the discovery. On this issue in order to have a better understanding, from the University of California at Santa Cruz (UCSC) calculation biologist David Haussler led a study group of five kinds of vertebrate animals - people, mice, rats , Chicken and blowfish - junk DNA sequences and four kinds of insects, worms, and two of the seven kinds of junk DNA sequence of yeast were compared. Researchers compared results from the received a surprising pattern: The more complex biological, junk DNA seems to be more important. This implied the possibility of which is that if different types of biological have the same DNA, then the DNA must be used to solve some key issues. Yeast and vertebrates share a certain number of DNA, after all, they need to manufacture protein, but only 15% of the total DNA and gene has nothing to do. Study group in July 14's "Genome Research" magazine online edition reported that they will yeast and more complex worms were compared, the latter is a multi-cell biology, found that 40 percent of the total DNA was not Coding. Subsequently, the researchers will vertebrate animals and insects were compared, these organisms more complex than worms, and found that more than 66% of the total DNA contains no coding DNA. Participate in the study calculated the UCSC biologist Adam Siepel said that the worm's findings need to carefully deal with, it is because scientists only on one of the two genomes were analyzed. Nevertheless, Siepel still believe that this has found strong support for such a theory, that is, invertebrates and insects in the biological complexity of the increase was mainly due to the fine mode of regulation. [DNA probe: [Edit this paragraph] DNA probe is the most commonly used DNA probe that several hundred base pairs in length above the double-stranded DNA or single chain DNA probe. The number of DNA probes have now been many, bacteria, viruses, protozoa, fungi, animals and human cells, DNA probes. Such probes for more than a gene sequence in whole or in part, or a non-coding sequences. These DNA fragments is to be specific, such as bacterial virulence factor gene probe and human Alu probe. These depend on access to the DNA probe molecular cloning technology development and applications. To bacteria as an example, the current hybridization technology for bacterial strain identification and classification of G + C than the percentage of value to be accurate, is the types of bacteria in a direction of development. In addition, hybridization of high sensitivity of hybridization in clinical microbiology diagnosis has broad prospects. The bacterial genome size of about 5 × 106bp, containing about 3,000 genes. Most of all between the DNA of bacteria is the same, to obtain a DNA probe specific bacteria, usually to take the establishment of bacterial genome DNA library approach, to be bacterial DNA into small fragments were cloned after the genome contains all the information Cloning library. Then use a variety of other strains of DNA probe to filter, a hybrid signal Cloning been removed, the last remaining and not any other bacterial hybrid cloning may contain the bacteria-specific DNA fragments. This recombinant probe after further identification tags can be identified by DNA sequence analysis of its genetic origin and function. So to get a specific DNA probe, is more often tedious. Screening of cloned DNA probe also serological methods may be, What is different is built for the DNA library can be expressed, or macrophage colony cloning spot after cracking the release of antigen, and then use the source of bacteria polyclonal anti-serum screening positive Cloning, which was cloned from a number of other bacteria via the anti-serum screening, with only the final anti-serum response to the bacterial clone that is the expression of this bacteria containing the specific gene fragments, it is the protein encoded by the unique species . Use this expression library is the only screening by a specific gene probe. [DNA repair: DNA repair (DNA repairing) is subject to DNA damage to cells after a reaction, this reaction may restore the original structure of DNA, can re-implementation of its original features, but sometimes can not completely eliminate the DNA damage, cells can only make This tolerance of DNA damage and can continue to survive. Perhaps this has not fully repair the damage will hold down the conditions for the show (such as the cancerous cells, etc.), but if cells do not have this repair, we can not deal with the frequent occurrence of DNA damage in the incident, can not survive . Therefore, DNA repair research is to explore an important aspect of life, but also with military medicine, oncology, and other closely related. The different DNA damage, cells can have different repair response. DNA contains A, C, G, T four bases, under normal circumstances A - T, C - G combination of the DNA base pairs that constitute the horizontal profile. Interpretation of genes is through DNA base sequences in order to convey instructions to the cells, the cells control work. Many factors will cause DNA strand breaks, DNA base pairs in the reorganization linked to rearrange, leading to the interpretation of the original base sequences and different, send the wrong direction, resulting in the wrong cell growth and work in, so in a cell mutation, Will also have the tumor cells. Tumor cells will absorb a lot of nutrients to the body or the fast-growing normal cells, cancer cells than normal cells to the large number of normal cells than 1-5 times, and more than a deformity, and so on. At the same time tumor DNA strands in the same situation will be broken, because DNA repair and a half with its own reservations about the function of reproduction, DNA ligase DNA fragments could be to link up again in the next rotation of the role of re-forming spiral. And a small section of DNA of tumor cells can be genetic characteristics of the new generation of tumor cells. Now scientists are often referred to cloning, the DNA is the use of this property. Therefore, most cases of cancer linked recombinant DNA is a change two or more of a change process, which form the tumor cell replication and propagation, which caused tumors on the expansion, proliferation, transfer and deterioration of the ultimate threat to human health And life. [DNA replication: DNA replication is double-stranded DNA in cell division before the copying process, is a copy of the results of two double-stranded into the same double-stranded (if the normal process of reproduction), each with double-stranded, like the original double-stranded . This process is called a half through replication mechanisms to retain the successful completion of the. Copy can be divided into the following phases: Start-up phase: helicase in the local start of the double helix structure of DNA molecules to single chain, the primer of identification initiation site, to unlock the section of DNA as a template, in accordance with the 5 'to 3' direction of short RNA chain. Formation of RNA primer. The formation of DNA fragments: a primer 3'-OH provided on the basis of the end, DNA polymerase chain by the two DNA replication process at the same time, because the process can only be reproduced by the 5'-> 3 'direction of synthesis, a chain To continuous synthesis, another section of a chain, each linked to become a short Okazaki fragment (Okazaki fragments). RNA hydrolysis primer: When DNA synthesis after a certain length, DNA polymerase hydrolysis RNA primer, Butian gap. DNA ligase to the DNA fragments of phosphate ester link up, form a complete DNA molecule. Finally the new synthetic DNA fragments in the rotation with the help of re-forming spiral. [Single chain DNA: Single chain DNA (single-stranded DNA) most of the DNA double helix structure exists, but a heat or alkali treatment will be linked into a single state. DNA is the single-chain refers to the existence of such a state of the DNA. Single-stranded DNA molecule in the nature of fluid dynamics, the absorption spectrum, bases and other aspects of the nature of response and different double-stranded DNA. Some phage particle containing single-chain ring of DNA, the phage DNA in the cell proliferation when a double-stranded DNA. [Closed-loop DNA: Closed-loop DNA (closed circular DNA) did not ring fracture of the double-stranded DNA, also known as the super-helix DNA. Due to their double-stranded helix structure of the closure, with the result that the entire DNA molecule and a further three Rotary song structure. Also if one or two different parts of the chain produce a fracture, it will become a Rotary song of the open-loop DNA molecule. Cells extracted from the plasmid or viral DNA contains the closed-loop and open loop that two kinds of elements. According to the two pigment can be combined with the ability of different, but the two hours to leave. [Link] DNA Linking DNA (Linker DNA): nuclear body, in addition to 146 bp DNA outside the core of all the DNA. [Template DNA] DNA template can be a single-chain molecules, it can also be a double-stranded molecule, can be linear elements, it can also be a ring of (linear elements than elements of the ring effect was amplified slightly better). On the template DNA, the impact PCR is the major factor in the number of templates and purity. [Complementary DNA: Complementary DNA (cDNA, complementary DNA) genes constitute the double-stranded DNA molecule with a single chain as a template, the transcription of a complementary sequence with the messenger RNA molecules, and then reverse transcription of the role, to mRNA molecules as a template, and a synthesis mRNA sequence complementary single chain DNA, and then a single-stranded DNA as a template of another single chain and its complementary DNA, two complementary single chain DNA molecules to form a double-stranded cDNA molecule, so the sequence of double-stranded cDNA With the transcription of the mRNA molecules of the gene is the same. Therefore, a cDNA molecules on behalf of a gene. CDNA but still different from the genes, because the gene transcripts produced in the mRNA, some non-coding sequences that introns are removed, retention The only coding sequence, Exon. CDNA sequences than so much shorter sequences, because cDNA gene is not included in the non-coding sequences - Intron.