Genetic structure in wild populations of black tiger shrimp (Penaeus monodon) using randomly amplified polymorphic DNA analysis

Randomly amplified polymorphic DNA (RAPD) analysis was used to examine gene tic variation in wild black tiger shrimp, Penaeus monodon. Specimens were c ollected from five geographically separated locations (Satun-Trang, Phangng a, and Medan in the Andaman Sea and Chumphon and Trad in the Gulf of Thaila nd). A total of 100 P. monodon individuals were investigated using seven ar bitrarily selected primers. Fifty-eight (72.5%) of eighty reproducible RAPD fragments ranging in size from 200 to 2200 bp were polymorphic. The percen tages of polymorphic bands of the five geographic populations investigated varied from 51.5 to 57.7%. The genetic distance between populations and UPG MA dendrograms indicated that the Medan population was genetically differen t from Thai P, monodon (D-ij = 14.976%). Within Thailand, the Satun-Trang P . rnonodon was separated from the remaining geographic populations with a g enetic distance of 2.632%, RAPD analysis in the present study yielded a tot al of 252 genotypes. A Monte Carlo analysis illustrated geographic heteroge neity in genotype frequencies within this species, suggesting that genetic population structure does exist in this taxon (P < 0.001 for all primers). Significant differences in genotype frequencies between Thai and Indonesian (Medan) P, monodon were observed (P < 0.0001), Within Thailand, the Andama n Sea P, monodon was significantly different from that of the Gulf of Thail and (P values between 0.0000 and 0.0387), indicating population differentia tion between P. monodon from these two main fishery regions of Thailand.