基于线粒体COI和16S rRNA基因研究3个地理群体黑龙江河蓝蛤的遗传多样性

摘要

采用通用引物对辽宁盘锦、辽宁大连、山东日照的3个地理群体黑龙江河蓝蛤(Potamocorbula amurensis)COI和16S rRNA序列进行扩增、测序分析,得到30条658bp的COI基因部分序列和27条450 bp的16S rRNA基因部分序列。其中COI和16S rRNA基因部分序列T、C、A、G和A+T的平均含量分别为45.4%和32.0%、13.5%和13.3%、20.7%和29.3%、20.4%和25.3%、66.1%和61.3%, AT含量高于GC含量,这与其他软体动物门动物的COI和16S rRNA的观测结果相近。COI和16S rRNA分别检测到了24个单倍型、43个核苷酸多态位点和9个单倍型、19个核苷酸多态性位点。AMOVA分析表明,3个群体间COI和16S rRNA部分基因总遗传分化系数分别为Fst =0.0090(P<0.001)和Fst =0.0674(P<0.001),群体内遗传分化远大于群体间、群体内存在较高的遗传分化。用 NJ 法构建分子进化树,3个地理群体的黑龙江河蓝蛤聚为一个族群,有少数个体和其他群体的个体聚在一起。%Mitochondrial COI and 16S rRNA gene fragments of three wild populations Potamocorbula amurensis were amplified with universal primers; the PCR products were sequenced, and 658 bp and 450 bp nucleotide se-quences were obtained. The T, C, A, G and A+T contents in the fragment (COI/16S rRNA) were 45.4%/32.0%, 13.5%/13.3%, 20.7%/29.3%, 20.4%/25.3%, and 66.1%/61.3%, respectively. The AT content was higher than the GC content. The phenomenon was similar to the results of other mollusca. 24 haplotypes and 43 polymorphisms were defined among COI from three populations. Nine (9) haplotypes and 19 polymorphisms were defined among 16S rRNA from three populations. The fixation indices (Fst) analyzed by AMOVA were totaled to Fst=0.0.0090 (P<0.001) and Fst=0.0674 (P<0.001), showing that the genetic fixation intra-populations was larger than inter-populations. It indicated that significant genetic fixation existed among the three populations. The Neighbor-joining (NJ) phy-logenetic trees were made from the three populations of P. amurensis, showing that the three populations might have originated from one clade, while a small number of individuals may be mixed in otherclades.