淮河水系日本沼虾群体遗传结构和系统演化的线粒体COI序列分析

测定了淮河水系17个日本沼虾(Macrobrachium nipponense)野生群体共248个个体的线粒体细胞色素氧化酶亚基I(COI)部分序列,获得623 bp核苷酸片段,包括48个变异位点,定义了31个单倍型,共享单倍型有12个,整体单倍型多样性和平均核苷酸多样性均处于中间水平。AMOVA分析表明,17个群体间的遗传分化系数Fst=0.041 3(P0.05),群体间遗传分化较小。Kimura 2-paramter遗传距离在五河与焦岗湖、花家湖及瓦埠湖群体间最大,为0.014,在高邮和邵伯湖群体之间最小,为0.003。MP系统树与单倍型进化网络关系图具有较高的一致性,31个单倍型被分为3个进化枝,其中一个进化枝主要以下游群体为主,另外2个进化枝主要以中游群体为主。群体中性检验、错配分析表明,淮河日本沼虾近期曾经历过种群扩张。

Genetic Structure and Phylogeography of Natural Macrobrachium nipponense Populations in Huaihe River Based on Mitochondrial COI Sequence

Genetic structure and phylogeography of seventeen natural populations of Macrobrachium nipponense in Huaihe River were analyzed based on mitochondrial Cytochrome Oxidase Subunit I (COI) gene sequence. Total DNA was extracted from 10-19 individuals of each population. A fragment of the 623 bp COI gene was amplified using the primers LCO1492 and HCO2198. 48 variable nucleotides were detected, and 31 haplotypes with 12 shared haplotypes were found in 17 populations. The result of haplotypic and nucleotide diversity analysis showed a middle genetic diversity. AMOVA analysis across all populations showed that there were low levels of genetic divergences among the 17 populations (F_st = 0.041 3, P<0.05). The Kimura 2-paramter genetic distance between Wuhe and Jiaogang, Huajia, Wabu populations (D_A= 0.014) was higher than that between other populations. UPGMA tree and haplotype network based on the 31 haplotypes indicated that the populations of the lower Huaihe River formed one clade and the populations of the middle Huaihe River formed the two others. The biomodel mismatch distribution of pairwise haplotype difference and the neutrality tests showed that population expansion occurred. These results would offer theoretical direction for the protection and utilization of the M.nipponense in Huaihe River.