缢蛏六群体16S rRNA基因片段序列的差异分析

The genetic diversity of mitochondrial 16S rRNA gene fragment in six populations of Sinonovacula constricta

采用PCR技术扩增了缢蛏线粒体DNA的16SrRNA基因片段,PCR产物经纯化、测序、同源序列比对获得长度为440bp的核苷酸序列。利用16SrRNA基因片段分析了江浙沪地区三个野生群体(江苏射阳、上海崇明、浙江象山)和三个养殖群体(江苏射阳、上海奉贤、浙江象山)的遗传多样性,共检测到了19个单倍型和41个核苷酸多态位点。序列分析结果显示,三个野生群体之间出现了明显的遗传分化,其中崇明群体遗传多样性最高,其次为射阳群体,象山群体遗传多样性最低,表明崇明群体未受到养殖群体基因的污染。在养殖群体之间则没有达到遗传分化,且单倍型混杂,聚类结果显示与象山野生群体亲缘关系最近,这表明长期的养殖过程在一定程度上对野生群体产生了影响,降低了种质资源的丰富度。

Mitochondrial 16S rRNA gene fragment of Sinonovacula constricta was amplified with polymerase chain reaction （PCR）. The PCR products were purified and sequenced from three wild populations： She-yang （WS）, Chong-ming （WC）, Xiang-shan （WX） and three cultured populations She-yang （CS）, Feng-xian （CF）, Xiang-Shan （CX） in Jiangsu, Zhejiang and Shanghai. 440 base-pair nucleotide sequences of 16 SrRNA were examined and analyzed for genetic polymorphism. Sequences data analysis showed that all 47 sequences were grouped into 19 haplotypes and there were 41 variable nucleotide positions in 16S rRNA gene fragments. The genetic diversity indexes were calculated and the results indicate that the significant genetic difference was observed among three wild populations, WC population has more variation than others, followed by WS population, WX population has the least sequence variation,which suggests that WC population has not been polluted by cultured populations. But there is no genetic difference among three cultured populations and it is closest to WX population. So the culturing process has reduced wild genetic diversity.