Microsatellite-based analysis of genetic variation in hatchery populations of Asian seabass, Lates calcarifer (BLOCH, 1790)

Abstract

Genetic variation based on microsatellite markers was comparatively analysed among 5 hatchery populations of Asian seabass, Lates calcarifer (BLOCH, 1790). Four samples were from the broodstocks of Krabi, Trang, Nakhon Si Thammarat and Rayong Coastal Fisheries Research and Development Center, and one sample from the Krabi progeny population. On the 12 microsateliite loci screened, LcaM27F (AF404089) was found to be the most polymorphic locus with 13 variant alleles, while only the locus LcaM06 (AF404075) was found to be monomorphic. Genetic variabilities including per locus and population averages of number of averaged alleles (Na), effective number of alleles (Ae), allelic richness (R), observed heterozygosity (Ho) and expected heterozygosity (He) were respectively as Na = 4.0000 – 4.9167, Ae = 2.5567 – 3.0947, R = 3.4510 – 3.8841, Ho = 0.5627 – 0.6278 and He = 0.5391 – 0.6092. Deviations from Hardy-Weinberg equilibrium (P_HWE>0.05) were found in some populations when the analyses were done over all loci. However, the amounts of genetic variation observed in the 5 populations were in the same level, and were lower than the level of wild and hatchery populations in Thailand reported by previous studies. The relative analyses of genetic structure and differences between populations showed that the 5 populations were genetically in the same group, with genetic differences between the populations within this group. Results from the analyses in each pair of populations together with the populations descriptive information made understanding in details of the populations and their genetic composition changes.

Due to genetic diversity level in the 5 hatchery populations of Asian seabass resulting from this study lower than the wild level, a recommendation is that broodstock populations of Asian seabass should be founded with higher level of genetic diversity to obtain the good quality and high potential broodstock for Thai aquaculture.