日本对虾养殖群体两个世代遗传结构的微卫星分析

Genetic structure analysis between two generations of cultured Marsupenaeus japonicas by microsatellite markers

中文关键词: 日本对虾  世代  遗传结构  遗传多样性  微卫星

英文关键词: Marsupenaeus japonicas  Generation  Genetic structure  Genetic diversity  Microsatellite

中文摘要:

      利用8对微卫星引物对日本对虾养殖群体两个世代的遗传结构进行了分析，共检测到108个等位基因，等位基因长度为196-528 bp，各位点等位基因数为6-23个。亲本和子代群体每个位点平均等位基因数目分别为8.5个和11.5个，平均观测杂合度分别为0.721和0.632，平均期望杂合度分别为0.775和0.764，平均多态信息含量分别为0.732和0.729。根据标记信息，利用最大似然法对两个世代的个体分别进行系谱结构推断，亲本群体划分为6个群体，群体间遗传距离为0.277-2.356，均值为1.510；子代群体划分为17个群体，群体间遗传距离为0-2.593，均值为1.113。亲本和子代分群体间的遗传距离变化范围为0-3.089，均值为1.238。根据各分群体间的Nei′s遗传距离，用非加权组平均法（UPGMA）构建了日本对虾两个世代的遗传进化树。其中18个分群体（4个亲本群体和14个子群体）经过聚类后形成3个分支，其余5个分群体（两个亲本群体和3个子群体）明显偏离于主支。研究发现，子代的观测杂合度明显低于亲本，说明子代在继承亲本遗传信息的过程中已经丢失了一定的杂合性。

英文摘要:

      The genetic structure for two generations of cultured Marsupenaeus japonicas was investigated using eight pairs of microsatellite primers. In this study, a total of 108 alleles were tested, and the length of the alleles ranged from 196 bp to 528 bp; the number of alleles per locus ranged from 6 to 23 with an average of 13.5. For the parents and offspring populations, the average number of alleles was 8.5 and 11.5, respectively; the observed heterozygosity was 0.721 and 0.632, respectively; the average expected heterozygosity was 0.775 and 0.764, respectively; and the average polymorphism information content was 0.732 and 0.729, respectively. The pedigree structure for the parents and progeny populations was inferred by maximum likelihood method according to the microsatellite marker information. The parent population was divided into six groups, and the genetic distance among them ranged from 0.277 to 2.356 with an average of 1.510. The offspring population was divided into 17 groups, and the genetic distance among them ranged from 0 to 2.593 with an average of 1.113. The genetic distance between parents and offspring sub-groups ranged from 0 to 3.089 with an average of 1.238. An evolutionary tree for the 23 sub-group populations was drawn by unweighted pair-group method with arithmetic means (UPGMA) according to Nei′s genetic distance. Eighteen sub-groups aggregated into the main stretch after forming three sub-stretches. However, five sub-groups (O15, O12, O13, P21 and P18) were obviously away from the main stretch. In this study, the heterozygosity and polymorphism of the offspring population were lower than their parents. The result showed that the heterozygosity of the parents have partially lost during the genetic inbreeding.