Detection of genetic variation in populations of black tiger prawn Penaeus monodon by dna fingerprinting

Abstract

Randomly amplified polymorphic DNA analysis (RAPD) was used to examine genetic variation of four geographically separated wild populations of Penaeus monodon from two regions: the Andaman Sea and the Gulf of Thailand Samples from the Andaman Sea were collected from Satun-Trang and Medan (Indonesia) and samples from the Gulf of Thailand were collected from Chonburi (Angsila district) and Trad. A total of 75 individuals were tested, which included 17, 28, 15 and 15 from Satun-Trang, Trad, Angsila and Medan respectively. A screen of 300 random decaoligonucleotide primers identified 7 primers, which were selected for the analysis of black tiger prawn DNA. A total of 80 reproducible RAPD fragments ranging in size from 200-2000 bp were scored and 62 fragments (77.5%) were polymorphic The percentages of polymorphic bands were 57.7, 52.2, 45.6 and 53.4% for samples from Satun-Trang Trad, Angsila and Medan respectively. The index of similarity within and between populations and genetic distances were performed based on the RAPD data. The values of genetic distance were used to construct dendrograms using arithmetic mean (UPGMA). The results of similarity index within population illustrated that the Angsila sample was the most similar among themselves. The results of similarity index between pouolations and UPGMA dendrograms showed that the Medan sample was significantly different from the 3 samples of Thai P. monodon. The results show that primer 428 detected a RAPD marker that was found only in samples from the Andaman Sea; Satun-Trang and Medan suggesting the use of this marker as a region-specific marker. RAPD patterns among the 4 samples gave 214 genotypes. One hundred and sixty of these were population-specific genotypes and 10 were region-specific genotypes. Ninety-seven of these genotypes were represented by a single individual. In chi-square analysis of the genotypes show that Thai and Indonesian P. monodon were significant different for all primers (P<0.0001) and Thai P. monodon from the Andaman Sea and the Gulf of Thailand were also different for primers 101, 268, 428, 457 and 459 (P=0.0049, <0.001, <0.0001, 0.0014 and 0.0156 respectively).