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DNA barcoding is a taxonomic method that uses a short genetic marker in an organism's DNA to identify it as belonging to a particular species. It differs from molecular phylogeny in that the main goal is not to determine patterns of relationship but to identify an unknown sample in terms of a preexisting classification.〔 Although barcodes are sometimes used in an effort to identify unknown species or assess whether species should be combined or separated, the utility of DNA barcoding for these purposes is subject to debate.〔 〕 The most commonly used barcode region, for animals, at least, is a segment of approximately 600 base pairs of the mitochondrial gene cytochrome oxidase I (COI). Applications include, for example, identifying plant leaves even when flowers or fruit are not available, identifying insect larvae (which may have fewer diagnostic characters than adults and are frequently less well-known), identifying the diet of an animal, based on its stomach contents or faeces and identifying products in commerce (for example, herbal supplements, wood, or skins and other animal parts).〔 == Choice of locus == A desirable locus for DNA barcoding should be standardized (so that large databases of sequences for that locus can be developed),〔 present in most of the taxa of interest and sequenceable without species-specific PCR primers,〔 short enough to be easily sequenced with current technology, and provide a large variation between species yet a relatively small amount of variation within a species. Although several loci have been suggested, a common set of standardized regions were selected by the respective committees: * For animals and many other eukaryotes, the mitochondrial COI gene * For plants, the concatenation of the rbcL and matK chloroplast genes. These provide poor resolution for land plants,〔 and a call was made for regions to be assessed that could complement rbcL and matK. * For fungi, the internal transcribed spacer (ITS) region 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「DNA barcoding」の詳細全文を読む スポンサード リンク
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