贵州黑山羊mtDNA Cytb基因遗传多样性分析

Sequence Analysis of Genetic Diversity of Mitochondrial Cytochrome b Gene from Guizhou Black Goats

[目的]研究分析了贵州黑山羊mtDNACytb基因的遗传多样性,为贵州黑山羊遗传资源的保护、开发及利用奠定分子遗传学方面的基础。[方法]测定贵州黑山羊品种16个个体的细胞色素b基因全序列,分析其碱基组成和序列间碱基的变异。[结果]在该品种(群体)中观察到6次T-C间发生碱基转换,其中有5个碱基替换发生在密码子第3位点,有1个碱基替换发生在密码子第1位点,且所有的变异均为同义突变;观察到4种单倍型。单倍型多样度(H)为0.442,核苷酸多样度(π值)为0.145%+0.159%。以绵羊为外群构建分子系统发生树,结果初步提示,贵州黑山羊有两个母系起源,其中支系A占81.25%(13/16),支系B占18.75%(3/16)。[结论]贵州黑山羊有两个母系起源(支系A和支系B),且该品种线粒体DNA多态度较为贫乏。

[ Objective] The research aimed to study the genetic diversity of mitoebondrial Cytochrome b gene from Guizhou blaeh goats, for helping to protect Guizhou black goat breed resource and offering molecular genetics foundation for exploitation and utilization. [ Method] The complete gene sequences in 16 individuals from Guizhou black goats were analyzed. [ Result] The results were as follow： 6 transitions were observed in this breed. 5 base substitutions in third codon positions and 1 base substitution in first codon positions, and all the substitutions were synonymous mutation. 4 different haplotypes were determined. The nucleotide diversity and haplotype diversity （H） was 0. 442, and the nucleotide diversity （Л value） was 0. 145 % ＋ 0. 159%. The molecular phylogenetic tree of mtDNA cytb of 16 individuals and 1 sheep individual was constructed by Neighbor-Joining method. The NJ tree indicated that Guizhou black goats had 2 types of maternal origin （ lineage A and lineage B）. The lineage A was 81.25 % and lineage B was l 8.75 %. [ Conclusion ] Guizhou black goats have 2 types of maternal origin （ lineage A and lineage B）, which showed that poor mitochondrial genetic diversity existed in Guizhou black goat breeds.