Author : See Leng Min

Summary : The giant freshwater prawn, Macrobrachium rosenbergii, or locally know as udang galah has become the most popular freshwater prawn for commercial culture and a significant cash crop for many poor farmers throughout Asia and the Pacific region. Ninety microsatellite repeat sequences were successfully isolated from M. rosenbergii using the 5' anchored-PCR technique. BLAST analysis of the microsatellite marker flanking regions showed similarities towards expressed sequence tags (ESTs) in aquatic species. Sixty-two microsatellite primer pairs were designed with 29 perfect microsatellites, four were imperfect or interrupted microsatellites and the rest were compound microsatellites. Of these 62 single locus DNA microsatellite markers, 24 showed polymorphisms in the giant freshwater prawns of which four loci had dinucleotide, 16 trinucleotide, three tetranucleotide and one pentanucleotide core repeat units. nine microsatellite primer pairs from the green-lipped mussel (Perna viridis) were successful in cross-amplifying the giant freshwater prawn genome. However, only four of these cross-amplified microsatellite primer pairs were reliable and used in this study. Hence, the levels of genetic variability in 12 populations of wild M. rosenbergii and one cultured population in Malaysia were evaluated by using 28 microsatellite loci. The number of alleles per locus ranged from 2 to 26 and the total observed heterozygosity ranged from 0.2618 to 0.7265.