线粒体序列分析黑龙江流域哲罗鲑的种群遗传结构

Genetic structure of Hucho taimen(Pallas) from Heilongjiang River as inferred from mtDNA sequence

哲罗鲑是我国土著的重要经济鱼类,近些年来,由于环境的恶化及人类活动的加剧,已对其资源量、栖息地、产卵场等造成了严重的破坏,种群处于濒危状态,被列入濒危物种红色名录中,因此研究哲罗鲑的群体遗传结构、演化历史、分布动态等对其进行有效保护具有重要意义。用线粒体Cox1和ND1基因序列对黑龙江流域内9个群体(n=30)进行了遗传结构、群体演化分析。在30个个体中,Cox1扩增出1550bp的片段,群体间序列分歧距离在0～0.0028之间,共发现10个单倍型;ND1基因扩增出1000bp的片段,群体间序列分歧距离在0～0.0013之间,共发现7个单倍型。单倍型网络(TCS)和AMOVA分析结果均表明黑龙江流域哲罗鲑存在显著的群体分化,Cox1基因、ND1基因及组合数据的群体间Fst分别为0.0704、0.0491、0.0792,均达到显著性水平(P<0.05),根据配对群体间Fst(Pairwised Fst)可以将黑龙江流域哲罗鲑群体分为黑龙江上游群体、呼玛河群体、乌苏里江群体、内蒙古伊敏河上游群体4个地理群。9个群体共享同一个单倍型(BH11),表明这些群体具有相同的演化历史,为同一个祖先群体(黑龙江上游群体)演化而来。

Taimen （Hucho taimen） is an important local wild commercial fishery species in Heilongjiang River. Due to severe damages to its population size, habitats, and spawning fields from overexploitation and environmental pollution. It is enlisted as an endangered species in the ＂China Red Data Book （Pisces）＂. To establish a scientific basis to conserve taimen, studies on the population genetic structure and phylogeography are necessary. In this paper, a total of 30 individuals, a selection from nine geographic areas along Heilongjiang River, were analyzed for genetic variances in their mitoehondrial Coxl （1550 bp） and ND1 （1000 bp） gene sequences. The sequence information identified 10 haplotypes in the Coxl gene. The average sequence divergence （Da） between individuals was 0. 0013, while it was 0 --0. 0022 within a population and 0- 0. 0028 between populations. Seven haplotypes of NDlwere also identified in this study. The average sequence divergence （Da） between individuals was 0. 0006, while the range within a population and between populations were both 0 --0. 0013. Fst values were 0. 0704, 0. 0491, and 0. 0792 for Cox1, ND1, and the combination of both genes. These data showed significant genetic variances （ P 〈 0.05 ） among geographic populations. The taimen populations in Heilongjiang River could be divided into four subpopulations based on Fst values between these geographic populations. However, these populations shared one common haplotype （BH11 ） shown by haplotype network （TCS） and haplotype distribution frequency analysis. This suggested that they evolved from a common ancestor （likely a population in the upstream of the Heilongjiang river） and shared common gene flows.