香螺线粒体COXⅠ和CYTB基因遗传多样性研究

Genetic diversity of mitochondrial COXⅠand CYTB genes in neptune whelk Neptunea cumingii

为探明香螺Neptunea cumingii遗传多样性水平及其种质资源背景,采用分子生物学技术对中国黄、渤海海域6个不同地理群体香螺COXⅠ和CYTB基因的遗传多样性进行比较分析。结果表明:COXⅠ基因序列长度为1536 bp,多态性位点141个,共定义COXⅠ单倍型11个,大连市大连湾群体(DL)的单倍型COXⅠ-10变异位点数最多(115个),群体内遗传多样性分析显示,大连湾群体的平均核苷酸差异数(K)和遗传多样性指数(P i)最高,分别为31.133和0.02121,群体间比较结果显示,烟台市八角港群体(YT)与蓬莱市长岛群体(PL)间的K值最低(2.094),大连湾群体与大连市旅顺盐场群体(LS)间的K值最高(24.971);CYTB基因序列全长为1140 bp,多态性位点34个,共定义单倍型14种,群体内遗传多样性分析显示,大连市獐子岛群体(ZZ)和大连市旅顺盐场群体的K和P i值最高,分别为13.444和0.01236,群体间比较结果显示,烟台市八角港群体与蓬莱市长岛群体间K值最低(1.395),大连湾群体与旅顺盐场群体间的K值最高(11.497);聚类分析结果显示,6个不同群体香螺的线粒体COXⅠ和CYTB基因有显著性差异,分子方差分析(AMOVA)显示,群体内变异远大于群体间差异。研究表明,不同海域香螺未出现明显的群体间差异,且群体内变异远大于群体间差异,不同海域间香螺未达到亚种分化。

In order to probe into genetic diversity and germplasm resources of neptune whelk Neptunea cumingii,genetic diversities of the COXⅠand CYTB genes were comparatively investigated in the neptune whelk collected from six different geographic groups in Yellow Sea and Bohai Sea in China including Dalian Bay(DL),waters of Zhangzidao County(ZZ),and Lushun Saltworks(LS)in coastal Dalian,Bajiao Bay Port(YT),waters in Weihai City(WH),and waters of Changdao County of Penglai City(PL)in Yantai from June to October in 2017 by molecular biology techniques.The results showed that the full COXⅠgene had the sequence of 1536 bp in length,141 variables sites and 11 haplotypes.There were 115 mutation sites of haplotype COXⅠ-10 in the Dalian Bay population in coastal Dalian(DL).Analysis of genetic diversity within the population revealed that the maximal number of nucleotide differences K(31.133)and nucleotide diversity index P i(0.02121)in the DL population.Analysis of genetic diversity among populations indicated that the minimal number of nucleotide differences K(2.094)was observed between the YT population and PL population,with the maximal number of K(24.971)between the DL population and LS population in Dalian.The full CYTB gene sequences were shown to be 1140 bp,34 variable sites and 14 haplotypes.Genetic diversity within the population showed that there were the maximal number of K in ZZ population(13.444)and P i in LS population(0.01236)in Dalian.Genetic diversity among populations indicated that there was the minimal nucleotide differences K(1.395)between the Yantai population and Penglai population,with the maximal(11.479)between the DL and LS populations.Cluster analysis showed that mitochondrial COXⅠand CYTB gene cluster was significant in six different waters.AMOVA analysis showed that intra-population variation was greater than inter-population difference.In conclusion,the differences of the neptune whelk among different populations were not obvious,the variation within the same population was much greater than the intergroup differences,and the neptune whelk among different populations did not reach the level of subspecies differentiation.