Genetic analyses of Asian seabass stocks using novel polymorphic microsatellites

To study genetic diversity of two cultured and one wild stock of Asian seabass (Lates calcarifer) in South-East Asia and their relationships, thirty-six polymorphic microsatellites were isolated from partial genomic libraries. The average allele number of the 36 microsatellites present among 32 individuals, was 7.4/locus, ranging from 2 to 17. One multiplex PCR set of nine polymorphic microsatellites was used to genotype 294 individuals from three stocks. High levels of allelic and genetic diversity were observed in all three stocks (average allele number = 8.2/locus and He = 0.75 in the wild stock; allele number = 9.6 and He = 0.76 in Singapore stock I; and allele number = 8.0 and He = 0.72 in Singapore stock II). FIS values within each stock were very low. Significant genetic differentiation (FST = 0.03, P < 0.05) and private alleles were detected among the three stocks. Thus, it may be possible to form a new superior broodstock with high genetic diversity by combining fish from different stocks. The developed polymorphic microsatellites, and especially the multiplex PCR set, are useful in monitoring genetic diversity of cultured stocks and for studying the genetic structure of wild stocks of Asian seabass.