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目前,我国西施舌群体分子遗传差异研究结果存在争议。分析我国南北沿海(9个群体)、与广西北海毗邻的越南(1个群体)西施舌核DNA的内转录间隔区2(ITS2)和线粒体DNA的16S rRNA基因(16S)片段核苷酸序列及其二级结构,为解决争议问题提供分子生物学资料。扩增获得西施舌ITS2片段和16S序列,其长度分别为389—402 bp和306 bp,加之下载序列共147条;序列分析显示,74个ITS2序列共有17种基因型,73个16S序列有15种单倍型,其中,长乐(CL)群体独享9种ITS2基因型和5种16S单倍型,非长乐群体(nCL)多数为群体间交叉共享1种或几种基因(单倍)型;基因(单倍)型核苷酸变异位点占5.7%(ITS2)和11.8%(16S);基于ITS2和16S的CL群体和nCL群体间的遗传距离与群体内遗传距离之比分别为2.42和11.08,nCL群体间的平均遗传距离均为0.007;二级结构显示CL群体ITS2的9种基因型和16S的5种单倍型均区别于nCL群体,nCL的ITS2和16S二级结构分别相似;ITS2和16S基因的系统发育分析显示,CL西施舌形成支持率很高(98,96)的单系支,而nCL群体则交叉聚为另一支(98,96)。研究结果揭示,福建西施舌是腔蛤蜊属(Coelomactra)的一个新种。
At present, the results of molecular genetic differences in Xishigia group in China are controversial. The nucleotide sequences of the ITS2 and 16S rRNA gene (16S) fragments of tongue tongue DNA of tongue and tongue of Vietnam (one population) adjacent to Guangxi Beihai were analyzed. Its secondary structure provides molecular biology information for the resolution of disputes. The ITS2 fragment and 16S sequence were amplified by PCR and their lengths were 389-402 bp and 306 bp, respectively. In addition, a total of 147 sequences were downloaded. Sequence analysis showed that 74 ITS2 sequences had 17 genotypes and 73 16S sequences had 15 Among them, nine CLS genotypes and five 16S haplotypes were found in the Changle (CL) population, and most of the non-Changle populations (nCL) were cross-shared with one or more genes (haplotypes) (ITS2) and 11.8% (16S), respectively. The ratio of genetic distance to intraspecific distance between CL population and nCL population based on ITS2 and 16S was 2.42 And 11.08, the average genetic distance between nCL populations was 0.007. Secondary structure showed that 9 genotypes of ITS2 and 5 haplotypes of 16S in CL population were all different from nCL population, and the secondary structures of ITS and 16S in nCL were similar Phylogenetic analysis of the ITS2 and 16S genes showed that the CL fingerlings formed single-branch support with high support (98,96), while the nCL group was cross-populated with the other branch (98,96). The results revealed that Fujian Xishi tongue is a new species of Coelomactra.