|
Transposons are semi-parasitic DNA sequences which can replicate and spread through the host's genome. They can be harnessed as a genetic tool for analysis of gene and protein function. The use of transposons is well-developed in ''Drosophila'' (in which P elements are most commonly used) and in Thale cress (''Arabidopsis thaliana'') and bacteria such as ''Escherichia coli'' (''E. coli'' ). Currently transposons can be used in genetic research and recombinant genetic engineering for insertional mutagenesis. Insertional mutagenesis is when transposons function as vectors to help remove and integrate genetic sequences. Given their relatively simple design and inherent ability to move DNA sequences, transposons are highly compatible at transducing genetic material, making them ideal genetic tools. ==Signature-Tagging Mutagenesis== Signature-tagging mutagenesis (also known as STM) is a technique focused on using transposable element insertion to determine the phenotype of a locus in an organism's genome. While genetic sequencing techniques can determine the genotype of a genome, they cannot determine the function or phenotypic expression of gene sequences. STM can bypass this issue by mutating a locus, causing it form a new phenotype; by comparing the observed phenotypic expressions of the mutated and unaltered locus, one can deduce the phenotypic expression of the locus. In STM, specially tagged transposons are inserted into an organism, such as a bacterium, and randomly integrated into the host genome. In theory, the modified mutant organism should express the altered gene, thus altering the phenotype. If a new phenotype is observed, the genome is sequenced and searched for tagged transposons.〔 If the site of transposon integration is found, then the locus may be responsible for expressing the phenotypes. There have been many studies conducted transposon based STM, most notably with the P elements〔 in ''Drosophila''. P elements are transposons originally described in ''Drosophila melanogaster'' genome capable of being artificially synthesized or spread to other ''Drosophila'' species through horizontal transfer.〔 In experimental trials, artificially created P elements and transposase genes are inserted into the genomes of ''Drosophila'' embryos. Subsequently, embryos that exhibit mutations have their genomes sequenced and compared, thus revealing the loci that have been affected by insertion and the roles of the loci.,〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Transposons as a genetic tool」の詳細全文を読む スポンサード リンク
|