利用mtDNA D-loop区研究中国10个绵羊品种的遗传多样性与起源

中国家绵羊的起源目前还不清楚,存在双起源说和三起源说,争论较大。为了进一步研究绵羊的起源和遗传多样性,根据已知家养绵羊(Ovis aries)线粒体基因组序列,利用 Primier premier5.0 设计引物,对我国 10 个家养绵羊品种 133 只个体的 mtDNA D-loop 区进行测序并利用 Laser Gene、MEGA4、Clustalx1.83 等软件对结果进行分析 ,结果标明,整个 D-loop 区为 1 106~1 182 bp,共检测到 103 种单倍型,155 个多态位点,表明我国家养绵羊品种遗传多样性丰富。通过构建 NJ 网络进化树,得出中国家养绵羊分为两个分支,羱羊(O. ammon)(AJ238300)与盘羊(O. vignei)(AY091490)聚为一类,而摩佛伦羊(O.musmon)(AY091487)与一个分支聚为另一类。说明,摩佛伦羊对中国家养绵羊起源与进化的贡献更大。本研究所测定的中国家养 10 个品种分为 A、B 两大支系表明家养绵羊至少有两大母系起源,且单倍型以亚洲 A 型为主。本研究从物种水平上评价了我国家养绵羊品种的遗传多样性,指出了中国家养绵羊分为两个分支,为确立中国家养绵羊种群关系和保护种质资源提供了理论依据。

Genetic Diversity and Origin of Ten Chinese Sheep(Ovis aries) Breeds Analyzed by Mitochondrial DNA D-loop Region

The origin of Chinese sheep is unclear yet. There is a large controversy between the Dual Origins and the Three Origins. For the further study on the origin and genetic diversty of sheep, the complete sequences of mitochondrial DNA(mtDNA) D-loop of 133 individuals in 10 Chinese sheep (Ovis areis) breeds were determined with primer pairs which were designed by Primier Premier 5.0 based on the sheep mitochondrial genome sequence. And the results were analyzed by the Laser Gene, MEGA4, Clustalx1.83 and other software. The results showed that the length of whole mtDNA D-loop of Chinese sheep was 1 106~1 182 bp. There were 103 different haplotypes and 155 polymorphic sites. The results indicated that Chinese domestic sheeps had abundant genetic diversity. The NJ tree results indicated that there were two main branches in Chinese domestic sheeps, O. musimon formed one of the branchs, while O. vignei and O. ammon was clustered together, which indicated that O. musimon had more contribution to Chinese domestic sheep breeds. Ten Chinese domesticated sheep species measured in this study were divided into two branches A and B, which indicated that there were at least two maternal origins and the Asia-A was the main haplotype.From the species level, this study evaluated the genetic diversity of domesticated sheep in China. It is pointed out that the Chinese sheep is divided into two branches, and a theoretical basis is provided for the establishment of the domesticated sheep populations relations in China and the protection of germplasm resources.