草鱼EST-SSRs标记的筛选及其与生长性状相关分析

利用草鱼(Ctenopharyngodon idella)EST(expressed sequence tags)数据库开发的18个EST-SSR标记,对草鱼群体进行基因型与生长性状关联分析和群体遗传多样性分析,结果表明:关联分析得到6个微卫星位点(13118、13305、24017、25085、35939和40698)与体重,体长和体高显著或极显著相关(P<0.05或P<0.01)。对其进行多重比较获得有利基因型分别为13118位点的BB、13305位点的AD、24017位点的AC、25085位点的BE、35939位点的BB和40698位点的BB。将6个微卫星位点上的EST序列与GenBank数据库进行BLAST比对,其中24017序列与鲤鱼自然杀伤细胞增强因子(NCEF)同源性水平高达86%,25085序列与草鱼反应元件结合蛋白(CREB)的基因同源性水平达到80%。应用这18个微卫星位点对草鱼养殖群体进行遗传多样性分析,共检测到82个等位基因,平均等位基因4.556个,每个位点检测到的等位基因数为2～9个,群体的平均观测杂合度为0.452 9,平均期望杂合度和平均多态信息含量分别为0.457 1和0.401 7,表明该群体遗传多样性处于低水平。

Detection of EST -SSRs markers in Ctenopharyngodon idellus and its association with growth traits

Eighteen pairs of EST-SSRs primers selected from EST base of Ctenopharyngodon idella were employed to examine the associations between their genotypes and growth traits and detect the genetic diversity of the cultured C.idella populations from.Microsatellite loci of 13118,13305,24017,25085,35939 and 40698 were significantly associated with body weight,body length.and body height(P<0.05 or P <0.01).The most favorable genotypes for growth traits were AA at 13118,AD at 13305,AC at 24017,BE at 25085,BB at 35939 and BB at 40698.The homology identity of the 6 correlative ESTs was determined by GenBank of NCBI blast programmer on the amino acid levels.It was found that 2 ESTs with significant similarity to the known functional sequences in GenBank.24017 was highly homologous to the known natural killer enhancing factor(NKEF) with an identity of 86%.25085 was highly homologous to the known cAMP-response element binding protein with an identity of 80%.The other 4 ESTs were not significantly homologous to any of the known functional genes from GenBank.In addition,2~9 alleles for each locus were detected.The average effective number of alleles(Ne),observed heterozygosity(Ho),expected heterozygosity(He) and mean polymorphic information content(PIC) was 4.556,0.4529,0.4571 and 0.4017,respectively,each of which indicated that the population genetic diversity was low.