基于DNA条形码对浙南岛屿日本花棘石鳖的遗传特征分析

Genetic polymorphisms of Liolophura japonica among the southern of Zhejiang Province based on DNA barcoding

采用COⅠ、16S rRNA两种分子标记对中国浙江南部沿海岛屿岩相潮间带日本花棘石鳖(Liolophura japonica)13个群体遗传特征和亲缘关系进行了探讨。结果显示:COⅠ基因片段长度为675 bp,16S rRNA基因长度为517 bp,A+T比例分别为62.5%和64.9%。COⅠ基因总多态位点数为41个,单倍型多样性指数0.847,核苷酸多态性指数为0.006 01,平均核苷酸差异数为4.057 8;16S rRNA基因的总多态位点数为9个,单倍型多样性指数0.665,核苷酸多态性指数为0.001 69,平均核苷酸差异数为0.871 2。以Acanthopleura brevispinosa和A.granulata为外群构建了ML和BI系统发育树,其拓扑结构显示,基于COⅠ基因的日本花棘石鳖形成2个分支;基于16S rRNA基因的日本花棘石鳖群体仅聚合为一支。不同地理群体单倍型散乱分布,没有出现明显的地理结构和遗传谱系结构,表明各岛屿的日本花棘石鳖为近期分化并存在基因交流。

Liolophura japonica Lischke belonging to Liolophura（ Mollusca： Polyplacophora： Chitonidae） is a common species in the southern of Zhejiang Province. Few study has been done on the population structure and genetic diversity of L. japonica. In order to discuss the population structure,genetic diversity and genetic background,we constructed the phylogenetic relationships of 13 geographical populations of L. japonica from the southern of Zhejiang Province using 675 bp length of mtDNA COⅠ and a 517 bp length of 16 S rRNA genes which can provid the basis data on its resource conservation and genetics utilization. The ratio of A ＋ T was62. 5% and 64. 9% in COⅠ and 16 S rRNA respectively,which was in accordance with the mitochondrial composition. The polymorphic loci,the parsimony informative sites,the single variable sites,the haplotype diversity index,the nucleotide polymorphism index and the average number of nucleotide differences in the COⅠ gene were 41,22,19,0. 847,0. 006 014 and 4. 057 8,respectively. A total of 30 haplotypes in COⅠgene were detected including haplotype 6 in the major haplotype. The polymorphic loci,the parsimony informative sites,the single variable sites,the haplotype diversity index,the nucleotide polymorphism index and the average number of nucleotide differences of 16 S rRNA gene were 9,4,5,0. 665,0. 0016 9 and0. 871 2,respectively. A total of 10 haplotypes of 16 S rRNA gene were detected. The phylogenetic tree of ML and BI in L. japonica was constructed using Acanthopleura brevispinosa and A. granulata as outgroups. The topological structure of L. japonica based on COⅠ gene in ML and BI analyses formed two clades while the topological structure based on 16 S rRNA gene in ML and BI analyses formed one clade. Different geographical population haplotypes were in scattered distribution and no obvious geographical structure and genetic lineage structure was found,which suggested that the gene divergence may happen recently.