不同鳊鲂鱼类群体微卫星DNA指纹图谱的构建和遗传结构分析

为对不同鳊鲂鱼类进行群体鉴定和遗传多样性分析,从60对微卫星标记中筛选出18对多态性高的引物,构建了6个鳊鲂鱼类群体的微卫星DNA指纹图谱。结果显示,东江三角鲂、钱塘江三角鲂、厚颌鲂、广东鲂、团头鲂和长春鳊6群体的平均等位基因数(N a)分别为5.17、6.11、3.50、6.56、5.22、5.22,平均期望杂合度(H e)分别为0.634 2、0.720 4、0.546 2、0.681 2、0.675 2、0.559 7,平均多态信息含量(PIC)分别为0.575 6、0.666 9、0.472 0、0.630 6、0.606 4、0.517 0,表明钱塘江三角鲂的遗传多样性最高,厚颌鲂的遗传多样性最低;聚类分析表明,钱塘江三角鲂和团头鲂首先聚为一支,遗传距离较近,为0.560 6;厚颌鲂与长春鳊的遗传距离最远,为1.759 2。引物Mam03和EST37产生的特异条带可将鲂属和鳊属鱼类区分,鉴定出鳊属鱼类长春鳊;引物TTF3、EST37、TTF2/TTF10、EST66依次组合可区分出鲂属东江三角鲂、厚颌鲂和广东鲂这3个群体。研究结果为我国鳊鲂鱼类种质资源保存、种群鉴定和良种选育奠定了基础。

Establishment of DNA fingerprinting and analysis on genetic structure of different Parabramis and Megalobrama populations with microsatellite

In the study,18 pairs of primers which could give stable and polymorphic amplification profiles were screened out from 60 microsatellite loci and used to analyze the genetic structure of Parabramis and Megalobrama species.Meanwhile,the microsatellite DNA fingerprinting in six populations of genera Parabramis and Megalobrama was established based on the results of alleles of microsatellite loci by Popgen1.32 software package and illustrative patterns were constructed by EXCEL office software,including two geographic populations of M.terminalis from Dong River(SJF1)and Qiantang River(SJF2),M.hoffmanni(GDF),M.pellegrini(HHF),M.amblycephala(TTF)and P.pekinensis(CCB).The results showed that a total of 221 alleles were obtained from the six genera Parabramis and Megalobrama populations,and the alleles ranged from 2-20 in each locus.The mean value of number on alleles(N_a)of SJF1,SJF2,HHF,GDF,TTF and CCB was 5.17,6.11,3.5,6.56,5.22 and 5.22,the mean value of expected heterozygosity(H_e)was 0.634 2,0.720 4,0.546 2,0.681 0,0.675 2 and 0.559 7,and the average value of polymorphism information content(PIC)was 0.575 6,0.666 9,0.472 0,0.630 6,0.606 4 and 0.517 0,respectively.It demonstrated that the genetic diversity of SJF2 was the highest and HHF was the lowest among the six populations.Using unweighted pair-group method with arithmetic means method(UPGMA)based on their genetic distances,the cluster analysis in six populations showed that SJF2 and TTF first grouped together,genetic distance was 0.560 6;then they clustered with SJF1,GDF,HHF,CCB in sequence;the genetic distance between HHF and CCB was 1.759 2,which was the farthest.In addition,nine pairs of specific microsatellite markers(TTF1,TTF2,TTF3,TTF7,TTF10,Mam03,Mam25,EST37 and EST66)were screened from microsatellite DNA fingerprinting which could be used to identify most of genera Parabramis and Megalobrama populations.Particularly,microsatellite primers(Mam03 or EST37)could differentiate P.pekinensis(CCB)from genus Megalobrama populations and microsatellite markers(TTF3,EST37,TTF2/TTF10,EST66)combination could completely identify SJF1,HHF and GDF populations among Megalobrama spp..However,as a result of the relative consistency of the genetic characteristics,specific SSR markers,which could distinguish M.terminalis from Qiantang River(SJF2)and M.amblycephala(TTF),were not found.Overall,these results could provide a theoretical basis for germplasm conservation,species identification and genetic breeding of genera Parabramis and Megalobrama in China.