基于线粒体DNA序列探讨中国紫貂的起源

lnvestigating the origin of M.zibellina in China based on mitochondrial sequence data

为了研究中国紫貂的起源,试验利用PCR方法和直接测序技术对中国境内分布的18只野生紫貂线粒体DNA控制区全序列进行了测定和群体分析。结果表明:所获得的7个单倍型序列长度介于1 073～1 134 bp之间,在保守序列区CSB1与CSB2之间存在AC串连重复序列,长度介于198～258 bp,这是导致紫貂线粒体控制区序列长度异质性的原因;序列中具119个碱基插入/缺失位点、2个颠换位点以及26个转换位点;其整体单倍型多样性(H)为0.880±0.045、核苷酸多样性(Pi)为0.039±0.004,种群总体遗传多样性水平较高。3个地理亚种间存在明显的遗传分化,尤其是长白山和阿尔泰亚种间FST(遗传分化指数)=0.989 49(P>0.01),种群间基因流极低(Nm=0.005);阿尔泰亚种、长白山亚种分别与大兴安岭亚种的个别种群存在较近的亲缘关系,该结论与紫貂化石证据结合即可推测出紫貂大兴安岭亚种是我国境内分布的3个紫貂种群中首先分化形成的,然后以大兴安岭为中心向南分化形成长白山亚种以及向西分化形成阿尔泰亚种。

To study the origin of M. zibella in China, The mitochondrial DNA control regions of 18 wild Sables collected in China were sequenced by polymerase chain reaction （PCR） and analysed. The results showed that the complete control regions in mt DNA from 7 haplotypes were located at 1073 - 1134 bp. There were AC repeat sequences located at 198 -258 bp fragment in conserved sequence block domain, which caused the sequence length heterogeneity of mitochondrial DNA control regions of Sable. There were 119 base insertion/deletion sites, 2 transversion sites and 26 transition sites. The overall haplotype diversity （Hd） was 0.88 ±0. 045, nucleotide diversity （Pi） was 0.039 ±0.004, the genetic diversity within population was high. Further analysis revealed that there was an obvious genetic divided among the three geographic subspecies,especially between the M. z. hamgyenensis and M. z. averini FST =0. 989 （P 〉0.01 ）. And the gene flow between the geographic locations sampled was relatively lower. The phylogenetic tree showed that M. z. averini and M. z. hamgyenensis had nearer relationship with the several population of M. z. princeps relatively. With this conclusion and the evidence of the Sable fossil it concludes that M. z. princeps of sable is the first differentiation species among the three populations for Sable, and then it differentiates and forms M. z. hamgyenensis in the south taking Greater Khingan mountains as the center and M. z. averini in the west relatively.