象山港黄墩支港菲律宾蛤仔种群COI和ITS1基因序列特征及遗传多样性分析

为了解象山港黄墩支港菲律宾蛤仔种质资源的遗传多样性现状, 采用COI和ITS1分子标记对该种群进行了基因序列特征和遗传多样性分析. 结果表明 在该种群30个个体中扩增得到的COI基因序列长度均为709bp, ITS1序列长度范围在693~729bp(共有746个位点). COI基因序列的位点中有670个保守位点(占94.50%)、39个变异位点(占5.50%); ITS1序列的位点中有保守位点671个(占89.95%)、变异位点62个(占8.31%)和缺失/插入位点13个(占1.74%). COI基因序列的保守性高于ITS1序列. 在COI基因序列中碱基(A+T)的占比(65.84%)高于(C+G), 而ITS1序列中则是碱基(A+T)占比(37.59%)低于(C+G). COI和ITS1序列的遗传距离分析均显示群体内遗传分化不明显. 基于COI基因序列和ITS1序列构建的遗传进化树显示 各科贝类分别相聚, 象山港菲律宾蛤仔位于帘蛤科的分支中, 其COI序列与杂色蛤进化关系最近. 遗传进化树中各种贝类的聚类关系与传统分类学结果相一致, 可作为分类的参考. COI和ITS1序列的平均核苷酸差异数分别为5.497和6.549, 核苷酸多样性指数分别为0.00775和0.00973, 单倍型数目分别为21和28, 单倍型多样性分别为0.963和0.993, 根据COI和ITS1两个序列计算得到的菲律宾蛤仔象山港群体单倍型多样性均大于0.5, 核苷酸多样性指数均大于0.005, 表明该种群遗传多样性丰富, 并处于稳定状态. 本研究结果补充了菲律宾蛤仔遗传多样性方面的研究资料, 并可为象山港菲律宾蛤仔种质资源保护和遗传育种提供理论基础.

Sequence characteristics and analysis of genetic diversity based on COI and ITS1 of Ruditapes philippinarum population at Huangdun area in Xiangshan Port

The present study was designed to understand the status of genetic diversity of Ruditapes philippinarum at Huangdun area in Xiangshan Port. A total number of 30 R. philippinarum samples were collected. The sequence characteristics and genetic diversity of COI and ITS1 molecular markers were analyzed. The results showed that the sequence lengths of COⅠ gene of the samples were all 709bp and the ITS1 sequence had total 746 loci. In addition, the sequence lengths were in the range of 693-729bp. In COⅠ gene sequence, there were 670 conserved sites (94.50%) and 39 variable sites (5.50%). There were 671 conserved sites (89.95%), 62 variable sites (8.31%) and 13 deletion/insertion sites (1.74%) in the total 746 loci of ITS1 sequence. The sequence conservation of COⅠ gene was significantly higher than that of ITS1 sequence. In COI gene sequence, the base content of (A+T) was 65.84% and was higher than (C+G). In the ITS1 sequence, the content of (A+T) was only 37.59% and was less than (C+G). The genetic distance analysis based on COI and ITS1 showed that there was no significant genetic difference between groups. The phylogenetic tree based on COⅠ and ITS1 showed that the shellfish of the same family grouped together. The R. philippiarum of was in the cluster of Veneridae and had the closest relationship of evolution to Venerupis variegata. The results of molecular phylogenetic tree were consistent with traditional classification. For R. philippiarum of , the average numbers of nucleotide differences were 5.497 for COI and 6.549 for ITS1. The nucleotide diversity indices were 0.00775 for COI and 0.00973 for ITS1. Haplotype numbers were 21 for COI and 28 for ITS1. Furthermore, haplotype diversity were 0.963 for COI and 0.993 for ITS1. The haplotype diversity of COⅠ and ITS1 were both greater than 0.5. The nucleotide diversity indices of these two sequences were both greater than 0.005. The results indicated that the R. philippinarum population at had rich genetic diversity and the genetic state was stable. The results provided theoretical basis for germplasm conservation and genetic breeding of the R. philippinarum population in