AFLP analysis of genetic diversity of importedLitopenaeus vannamei populations and cultured stocks

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 estimatedΦ_ST 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..