贵州黑山羊mtDNA Cytb基因遗传多样性分析

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。

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

Objective] The research aimed to study the genetic diversity of mitochondrial Cytochrome b gene from Guizhou blach 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(π 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 18.75%.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.