6个地方鸡种线粒体 COⅠ基因的DNA条形码研究

本研究利用线粒体细胞色素C氧化酶I (cytochrome c oxidase ⅠCOⅠ)这一特定基因的特定区段来做DNA条形编码的基础，选择其中二段序列（Bar1 Bar2）设计2个引物对6个中国地方鸡种的线粒体DNA进行扩增，以对其进行种品鉴定。本研究选择的2段序列中，以Bar1序列648bp（712位点到1359位点）多态性最高，突变位点最多，为24个，品种间平均多态性为3.860%，6个鸡种在此序列中有各自不同的特异位点，NJ聚类分析6个品种基本被聚为不同的类别，与形态学分类基本一致，该COⅠ基因的Bar1序列用于这些品种鉴定是可行的；而Bar2序列进行序列多态性分析，由于其多态性低，大多品种没有其特异位点，NJ聚类分析6个品种基本被聚为不同的类别，与形态学分类基本一致，不利于品种鉴定。从本研究结果看，利用COⅠ基因的DNA条形编码（DNA Barcodes）进行不同鸡品种鉴定具有方便、快捷、经济、准确等优点，结合传统形态学鉴定手段将会揭示更深层次的遗传多样性和系统进化关系, 经过进一步改进是用于品种鉴定的优良工具。

The DNA Barcoding Application of mtDNA COⅠGenes in Six Indigenous Chicken Breeds in China

In this research DNA Barcodes was based on the special section of the cytochrome c oxidase 1 (COⅠ)sequence. Three primers were designed in three special sections(Bar1 Bar2) to identify six indigenous chicken breeds. The Bar1 sequence of COⅠ(648 bp : from 712 sites to 1358 sites) was the highest in polymorphism and had 24 SNP in six chicken breeds. The average interspecific divergence was 3.860%, and special sites were found in each chicken breed which was the bases to identifying chicken breeds. The DNA taxonomy of Bar1 used NJ was consistent with morphological taxonomy among the six indigenous chicken breeds. However, the analysis of Bar2 sequences of COⅠindicated that they were lower polymorphism and no special site in most chicken breeds which was not benefit to identify chicken breeds. The DNA taxonomy of Bar2 used NJ was not consistent with morphological taxonomy among the six indigenous chicken breeds. The results illustrated that the DNA barcoding was a rapid and inexpensive method for the identifying breeds, especially when coupled with traditional taxonomic tools in disclosing hidden diversity and molecular phylogeny relationship. It was a better tool for identifying chicken breeds through more improvement.