3种色型仿刺参线粒体和核糖体序列片段遗传结构比较研究

Comparative study on genetic structure of three color variants of the sea cucumber (Apostichopus japonicus) based on mitochondrial and ribosomal genes

仿刺参作为我国重要的海水养殖物种,良种选育是目前研究的重点,其中体色是重要的考虑因素之一。为了比较3种不同体色仿刺参的遗传结构,采用PCR扩增与测序技术对我国3种体色(青色、白色和紫色)仿刺参线粒体16S rRNA和COⅠ与核糖体18S rRNA-ITS-28S rRNA序列片段进行分析,揭示其遗传结构差异及系统发育关系。结果表明,16S rRNA、COⅠ和18S rRNA-ITS-28S rRNA序列长度分别为812~830 bp、877~915 bp、1536~1572 bp。16S rRNA、COⅠ和18S rRNA-ITS-28S rRNA序列在青色、紫色和白色仿刺参中分别检测到单倍型个数分别为4/5/5、5/3/4和4/4/3,COⅠ序列多态性位点数目所比例最大,16S rRNA序列最小。3种色型仿刺参16S rRNA、COⅠ和18S rRNA-ITS-28S rRNA序列遗传距离数值均比较小,范围分别为0~0.0147、0~0.0212和0~0.0103,没有达到种的分化水平。以紫海胆为外群,基于COⅠ序列构建系统发育树,结果表明白刺参单独聚为一支,但是紫色和青色仿刺参不同个体间相互交叉聚集,无法通过发育树区分。

The sea cucumber Apostichopus japonicus is an important marine aquatic species in China.Selecting good breeding is a major issue for sea cucumber aquaculture,and body color is chosen as an important consideration.In order to explore the genetic structure and phylogenetic relationship of sea cucumber populations with different body color characteristics,16 S rRNA,COⅠand 18 S rRNA-ITS-28 S rRNA sequences were amplified and sequenced.The results showed that the lengths of 16 S rRNA,COⅠand 18 S rRNA-ITS-28 S rRNA sequences were 812-830 bp,877-915 bp and 1536-1572 bp,respectively.In the green,white and purple morphs of the sea cucumber,4/5/5,5/3/4,and 4/4/3 haplotypes were detected in 16 S rRNA,COⅠand 18 S rRNA-ITS-28 S rRNA sequences,respectively.The number of polymorphic loci in the COⅠsequences was the highest,and that of 16 S rRNA sequences was the smallest.The genetic distances of 16 S rRNA,COⅠand 18 S rRNA-ITS-28 S rRNA sequences among three color morphs were both small,ranging from 0-0.0147,0-0.0212,and 0-0.0103,respectively,and they did not reach the species differentiation level.The phylogenetic tree was constructed based on the COⅠsequences,and Strongylocentrotus purpuratus was chose as the outgroup.The results showed that the white sea cucumbers were clustered into one branch,the purple and green sea cucumbers were cross-aggregated with each other and could not be distinguished.