4种河蓝蛤线粒体COI和16S rRNA基因序列的种间遗传分析

Genetic analysis of mitochondrial COI and 16S rRNA gene fragments in four Potamocorbulaspecies

对光滑河蓝蛤Potamocorbula laevis、黑龙江河蓝蛤P.amurensis、焦河蓝蛤P.ustulata、红肉河蓝蛤P.rubromuscula4个野生种共40个个体的线粒体COI和16SrRNA基因片段进行了扩增和测序,经过筛选和剪切,得到长度为650bp和450bp的片段。序列分析显示,序列的碱基组成中G+C含量较低,16SrRNA基因种间和种内的变异较低,COI基因片段种内和种间的变异较高。以沙海螂Mya arenaria为外群,用MEGA 4.0软件中的NJ法构建了系统进化树,通过遗传距离和系统进化树可以看出,4种河蓝蛤未能达到不同种之间显著的遗传分化。

The gene fragments of the mitochondrial COI and 16S rRNA in Potamocorbula laevis, P. amurensis, P. ustulata and P. rubromuscula were amplified and sequenced. Total- ly, 40 sequences of COI gene and 16S rRNA were obtained, and after trimming they were 650 bp and 450 bp respectively in length with low GC content. The results of sequence analysis showed that the intraspecific variation and interspecific variation were lower in 16S rRNA than those in COI gene. Ten mutation sites and seven haplotypes were detected in the gene fragments of 16S rRNA. Taking Mya arenaria as the out-group, the phylogenetic trees of COI and 16S rRNA were constructed by the neighbor-joining （NJ） method using software MEGA 4.0. Based on the genetic distance in NJ phylogenetic tree,we found that the four species of Potamocorbula failed to achieve significant genetic differentiation between species.