DNA probe

DNA probe is the most commonly used DNA probe, saying that a few hundred base pairs in length than the double-stranded DNA or single-stranded DNA probe. DNA probe has been a lot of volume, there are bacteria, viruses, protozoa, fungi, animals and human cell DNA probe. 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 factors and human probe gene Alu probe. These DNA probe was dependent on the molecular cloning technology and applications. By bacteria, for example, the current hybridization for bacterial classification and identification of bacteria than the percentage of the value of G + C to be more accurate, is a bacterial taxonomy development. In addition, hybridization of high sensitivity of the hybridization in clinical diagnosis of micro-organisms has broad prospects. The bacterial genome size of about 5 × 106bp, with about 3,000 genes. The vast majority of among a variety of bacterial DNA is the same, it is necessary to obtain a bacteria-specific DNA probe is usually taken to the establishment of bacterial genomic DNA library of the way, is about to bacterial DNA into small fragments were cloned to be included in post-genome-wide information Cloning library. And then use a variety of other strains of DNA probe for screening to produce hybrid cloning signals were taken out, the last remaining non-hybrid with any other bacterial cloning may contain the bacteria-specific DNA fragment. This recombinant plasmid probe after further identification tags can also be identified by DNA sequence analysis of their genetic origin and function. Therefore, to be a specific DNA probe, is more often tedious. Cloning DNA probes can also filter the serological method, the difference is that the library to be built DNA expression, cloning colony or plaque by cracking after the release of antigen expression, then the source of the bacteria polyclonal anti-serum screening positive Cloning, the positive clones from a number of other bacteria to be passed by the anti-serum screening, only with the bacteria response to the expression of anti-serum that contains the bacterial cloning of specific gene fragments, it is the protein encoded by the strain-specific . Using this expression library screening to be clear that only the specific gene probe.