AFLP analysis of genetic diversity of shrimp Litopenaeus vannamei.

【Objective】The study was done to evaluate the genetic diversity of cultured Litopenaeus vannamei in order to provide a technical basis for inheritance breeding work.【Method】Amplified fragment length polymorphism(AFLP)technique has been used to analyze the genetic variation among a total of 350 indiciduals representing 35 families of L.vannamei.The number of polymorphic loci was counted.Popgene Version 1.31,Arlequin Version 3.1 and Mega 3.1 were taken to calculate the genetic diversity index of the families of Shannon's genetic diversity index and the genetic differentiation index of Fst.Cluster analysis was performed between 350 individuals of 35 families using UPGMA method based the Nei's distance.【Result】Ten pairs of selective primers produced 162 polymorphic markers out of 312 bands amplified.The percentage of polymorphic loci was 51.92%.The percentage of polymorphic loci and Shannon index among families was between 12.50%-32.69% and 0.068 3-0.181 7. AMOVA(Analysis of molecular variance) showed that 63.62% of genetic variation resided within families,while 36.38% of genetic variation resided between families,representing the genetic differentiation index of Fst 0.363 8.Via Fst,the Nm 0.937 2.【Conclusion】The Litopenaeus vannamei for examination was on a high level of genetic diversity,and had some indeed selective capacity.Fst showed that the most genetic variation resided within families,Nm showed that limited gene flowing was the main cause of the genetic variation,which indicated the whole 35 families formed a relatively independent system during breeding.The cluster analysis declined the evolution relationship among families,which could provide a basis for the future breeding work.