Studies On Sex-specific AFLP Markers And Genetic Structure Among Three Cultured Populations In Claris Fuscus

Claris fuscus, an important cultivated population in GuangDong，GuangXi andFuJian province，China, were selected as our experimental animal. Up to now, studiesconcentrated in the propagation and aquaculture technologies on Claris fuscus, and littlewas known about genetic diversity,germplasm resouces, cultivation conditions, andsex-specificmarkers. In this study,genetic structure of three cultured populations（FuJian,JiangMen and YuLin）, diffirence between parents and their offspring, and sex-specificAFLP markers were analyzed by AFLP technique on C. fuscus. Main results as follows:（1）Genetic diversities of90individuals（30each population）from threepopulations of XiaMen（XM）, JiangMen（JM）and YuLin（YL）were analyzed. Fivefrom64primer-combinations displayed a total of289AFLP loci. The percentage ofpolymorphic loci was between47.8%and63.8%, and averaged56.4%. The average totalgenetic diversity（Ht）, the average genetic diversity within populations（Hs）, the genedifferentiation coefficient（Gst）, and the gene flow indes（Nm）was0.1611,0.1536,0.0511, and8.5018, respectively. Results showed that the gene diversity index of C.fuscus was in good condition, and the genetic variation mainly came from individualswithin populations but not between cultured populations. Compared to the XM and YLpopulation, JM displayed well polymorphic, higher Nei’s gene diversity and Shannongenetic diversity index. Among the3cultured populations, XM and YL populationsdisplayed the largest differentiation, then between XM and JM, and the smallest betweenJM and YL.（2）Six primer-combinations displayed a total of326AFLP loci from60individuals in parents and their offspring（YL population）. The average percentage ofpolymorphic loci was25%, and the effective number of alleles was1.0405. Ne,Shannon’s Informationinde, Ht, Hs and Nm was0.1267,0.2047,0.1387,0.1336,0.0367,and13.1422, respectively between parents and their offspring. Result showed that thelower polymorphism in offspring might result from the close crossing and the lesserparents, and suggested that the management of parental generation should bestrengthened to ensure the sustainable development of C. fuscus breeding.（3）144primer-combinations were used to screen the genome DNA of C. fuscus,but no sex-specific markers were found. Result suggested that the lesser sex-specific fragments and primes, and inappropriate endonucleases used in C. fuscus might beresponsible for that.