河北3个日本沼虾野生群体线粒体DNA D-Loop基因序列变异及种群遗传结构分析

Genetic variation analysis of three wild populations of Oriental river prawn (Macrobrachium nipponense) in Hebei Province with mtDNA D-Loop sequences

为进一步了解白洋淀与衡水湖日本沼虾种质资源现状,实验通过对白洋淀南淀(SB)、白洋淀北淀(NB)、衡水湖(HS)日本沼虾群体线粒体DNA D-Loop基因片段进行扩增和测定,得到935 bp的序列用于进一步的分析,其中变异位点80个,占分析位点的8.56%,含有77个简约信息位点,平均转颠换比值(TS/TV)为7.28,4种碱基在所得序列中平均含量为A(42.65%)、G(9.08%)、T(36.98%)、C(11.29%),其中A+T含量为79.63%,明显高于C+G含量。AMOVA分析结果显示,群体间的遗传分化系数FST=0.2336,群体间遗传变异占23.36%,群体内遗传变异占76.64%,群体间具有较高程度的遗传分化。运用K-2-P模型构建了3群体的23个单倍型的NJ系统发育树,单倍型之间并没有按照单倍型所属群体的分类聚簇,表现为不同群体个体相互交错形成复杂的簇群。群体中性检验、错配分析表明,日本沼虾近期未曾经历过种群扩张。

In order to understand further the genetic resources of Macrobrachium nipponense in South Baiyangdian（SB）, North Baiyangdian（NB） and Hengshui Lake（HS） of Hebei Province, we investigated the genetic structure of Oriental river prawn M. nipponense among three different wild populations from Baiyangdian and Hengshui Lake of Hebei Province using nucleotide sequences from control region（D-Loop） gene of mitochondria. The results revealed polymorphisns at 80 nucleotide sites from an approximately 935 bp fragment of this gene region sequenced, accounting for 8.56% of all sites, of which 77 were parsimony-informative sites, the contents of A, T, G and C of D-loop were 42.65%, 36.98%, 9.08% and 11.29%, respectively, and the content of A＋T（79.63%） was significantly higher than that of G＋C. The fixation indices（FST） analyzed by AMOVA of ARLEQUIN Version 3.11 was 0.2336, which indicated that the variation percentages between and within groups were 23.36% and 76.64%, respectively. NJ phylogenetic tree of 23 haplotypes constructed by Kimura-2-parameter model showed haplotypes did not cluster in accordance with the group of haploid type, but characterized by different groups with individual interlaced form complex cluster. The mismatch distribution analysis and neutrality test demonstrated that M. nipponense has not experenced a population expansion recently.