基于SSR标记分析15个凡纳滨对虾家系遗传多样性和遗传结构

Genetic diversity and structure of 15 full-sib families of Litopenaeus vannamei based on SSR markers

摘要:

为明确凡纳滨对虾(Litopenaeus vannamei) F1代核心群体的遗传多样性和遗传结构，本研究利用15对多态性较高的微卫星引物对15个凡纳滨对虾全同胞家系进行简单重复序列(simple sequence repeat, SSR)分子标记和遗传多样性分析。结果显示，在选择的15个SSRs位点中，共检测出112个等位基因(number of alleles, N_a)，60.453个有效等位基因(number of effective alleles, N_e)，多态性信息含量(polymorphism information content, PIC)均值为0.648。15个F1代核心选育家系的平均N_e为1.925–2.626，平均观测杂合度(observed heterozygosity, H_o)为0.425–0.783，平均期望杂合度(expected heterozygosity, H_e)为0.403–0.572。聚类分析表明，15个家系主要分为3个类群，遗传距离在0.252–0.574之间。各家系间遗传分化系数(fixation index, F_st)为0.112–0.278，表明群体间存在较大的遗传分化。本研究证明15个凡纳滨对虾家系的遗传多样性适中，为后续耐受高水平豆粕饲料的凡纳滨对虾家系选育工作提供了遗传学证据。

关键词:凡纳滨对虾;分子标记;核心育种群体;遗传多样性;遗传结构

Abstract:

To clarify the genetic diversity and structure of the nucleus population of F1-generation Litopenaeus vannamei, this study utilized 15 pairs of highly polymorphic microsatellite primers to analyze the simple sequence repeat (SSR) markers and genetic diversity in 15 full-sib families of L. vannamei. A total of 112 alleles (N_a) and 60.453 effective alleles (N_e) were identified among the selected 15 SSR loci, with the average polymorphic information content (PIC) of 0.648. The average N_e, observed heterozygosity (H_o), and expected heterozygosity (H_e) in the 15 F1 families varied from 1.925 to 2.626, 0.425 to 0.783, and 0.403 to 0.572, respectively. The 15 full-sib families were primarily clustered into three categories in the phylogenetic analysis, with the genetic distance between families ranging from 0.252 to 0.574. Additionally, the genetic differentiation coefficient (F_st) among the families varied from 0.112 to 0.278, indicating substantial genetic differentiation. Overall, this study suggested that the genetic diversity of the 15 full-sib families was moderate, providing valuable genetic insights for the subsequent breeding initiatives aimed at enhancing the tolerance of L. vannamei to high levels of soybean meal.

Key words:Litopenaeus vannamei;molecular markers;nucleus population;genetic diversity;genetic structure