Genetic variability and differentiation of feral and cultured populations of asian sea bass (lates ca/carijer) in Malaysia inferred by microsatellites
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Date
2008-06
Authors
Choay Hoong, Lai
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Abstract
Ten microsatellite loci were used to investigate genetic variability and differentiation of
three feral (Pulau Sayak, Semerak and Tanjung Piandang) and six cultured (Pulau
Sayak, Sungai Linggi, Merchang, Sungai Pendas, Punang and Sematan) populations of
Asian sea bass, Lates calcarifer in Malaysia. Level of allelic richness (Ar) ranged from
2.0-11.3 while expected heterozygosities (He) ranged from 0.234 to 0.875. All feral
populations exhibited almost similar and high levels of genetic variation. Genetic
variation in terms of expected heterozygosity (He) and allele richness was slightly lower
in three (Sungai Pendas, Punang and Sematan) of five hatchery samples than in samples
of the feral populations. The Sematan cultured population exhibited a mode shift in its
allele frequency distribution which suggests a recent bottleneck has occurred. Pairwise
estimates of genetic differentiation between feral populations were low (Fsr = 0.0310-
0.0899) but moderately high among cultured populations (Fsr = 0.0252-0.1637),
suggesting occurrence of genetic drift in the hatcheries with each hatchery practicing
different management regime. This demonstrates the need for introduction of healthy
genetic materials, genetic monitoring and effective breeding programs to ensure the
genetic health of the Asian sea bass in Malaysia. STRUCTURE analysis suggests that
the most likely number of cluster (K) for nine the populations in this study was equal to
six. Based on results of pairwise Fsr values and Individual Assignment Tests, both
Pulau Sayak-F and Semerak were suggested to have received either introductions of
populations representing all the six clusters or represent the ancestral population of the
species, thus contributing to the observed admixture in the populations
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Keywords
Cultured populations , Malaysia inferred by microsatellites