Microsatellite polymorphism and the population structure of the black tiger shrimp (Penaeus monodon) in Thailand

Genetic variation and differentiation of Thai Penaeus monodon from five geo graphic locations (Chumphon, Trad, Phangnga, Satun, and Trang) were investi gated using five microsatellite loci (UPmo18, Di25, Di27, CSCUPmo1, and CSC UPmo2). The number of alleles across the five loci ranged from 19 to 30, an d heterozygosities ranged from 0.49 to 0.95. The mean number of alleles and effective number of alleles per locus were 21.0 to 26.6 and 13.1 to 20.4, respectively. The average heterozygosity across all investigated samples wa s 0.78, indicating high genetic diversity in this species. Geographic heter ogeneity analysis of the results from two of the loci, CUPmo18 and Di25, sh owed significant differences among the Gulf of Thailand (Trad and Chumphon) but not the Andaman samples. Comparison between regions revealed significa nt heterogeneity of the Andaman and Trad P. monodon (P < .001), whereas tho se from Chumphon and the Andaman were genetically similar (P > .05). Signif icant genetic differentiation was consistently observed between the Andaman -Trad samples (F-ST = 0.0101, P < .0001) and the Chumphon-Trad samples (F-S T = 0.0101, P < .0001). On the basis of our analyses, the investigated samp les from five geographic locations were allocated to three distinct populat ions composed of the Andaman Sea (A), Chumphon (B), and Trad (C).