Genetic divergence between two marine catfish of family Ariidae - Arius maculatus and Osteogeneiosus militaris

Abstract

Two species of marine catfish, Arius maculatus and Osteogeneiosus militaris, belonging to Family Ariidae were analysed electrophoretically for genetic variation in 6 enzymes, alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), lactate dehydrogenase (LDH), glucose dehydrogenase (GDH), malic enzyme (ME) and superoxide dismutase (SOD). Eighteen individuals of each species were studied. Two loci MDH and ADH were polymorphic in both. Average heterozygosity in A. maculatus was 1.46. while it was 2.5 in O. militaris. The allele frequencies were used to estimate Nei's genetic distance (D). The D value was calculated to be 0.6879. Two isozyme loci, ME and SOD, were found to be the most reliable species specific markers. No tissue specific loci were observed for the enzymes studied, the bands being identical in each case. The genetic distance observed between O. militaris and A. maculatus in this study suggests that they would be more appropriately classified as species of the same genus rather than being assigned separate genera.