凡纳滨对虾引进群体与养殖群体遗传多样性的AFLP分析

摘要

The white shrimp,Litopenaeus vannamei,is one of the most important aquaculture species in China.The broodstocks used in China are mainly introduced from abroad.Recently,several new domestic white shrimp strains have been bred and used as broodstock.To further strengthen the genetic breeding of white shrimp,it is necessary to understand genetic diversity status of different strains.In the present study,the amplified fragment length polymorphism (AFLP) was employed to analyze the population genetic diversity and genetic difference between four introduced populations and three domestic breeding populations.A total of 105 fragments in length of 100～500 bp were identified from 210 individuals using seven AFLP primer combinations,of which 90 of 105 fragments were polymorphic,and the proportion of polymorphic loci was 85.71％.The polymorphic loci within populations varied from 54.17％ to 65.63％,with an average of 60.53％,and the mean heterozygosities ranged from 0.164 to 0.236,with an average of 0.202.AMOVA analysis revealed that 51.79％ of genetic variations derived from populations,the estimated ΦST value over all polymorphic loci across the seven populations was 0.518,indicating significant genetic differences between populations and strong population structure.Furthermore,these results could provide theoretical supports for germplasm improvement ofL.Vannamei..%为了解引进群体与国内养殖凡纳滨对虾群体遗传多样性水平,提高我国凡纳滨对虾种质改良效果,应用AFLP标记技术对国外引进群体和国内养殖凡纳滨对虾群体的遗传多样性进行分析.采用7对AFLP引物组合对7个群体(4个引进群体,3个养殖群体)210个个体进行扩增,结果发现,7个群体在100～500 bp共检测到105个位点,其中多态性位点为90个,多态位点比例为85.71％.4个引进群体(KONABA、SISMAN、OI、CHAI)的多态性位点百分率分别为62.5％,57.29％,61.21％,61.46％;3个国内养殖群体(ZX、ZK、GDOU)的多态性位点百分率分别为65.63％,61.46％,54.17％.7个群体的平均期望杂合度为0.202,表明所检测的7个群体均具有较高的遗传多样性.AMOVA分析显示,51.79％的变异来源于群体间,群体的平均ΦsT值为0.518,表明凡纳滨对虾群体内遗传多样性非常丰富,群体间相似性较大,且存在较强的基因交流.本研究可为我国凡纳滨对虾种质改良提供基础资料.