Morpho-genetic Analysis of Three River Populations of Bhagna, Labeo ariza (Hamilton 1807) in Bangladesh

Abstract

Morphological and genetical analysis of Bhagna Labeo ariza H. populations was investigated from three river populations (the Atrai, the Jamuna and the Brahmaputra) of Bangladesh to identify its diversified populations. Therefore, about 30 similar size of fish samples were collected from each of those three river populations and analyzed nine morphometric and meristic characters and their genetic variation by allozyme markers. All of the morphometric characters were significantly higher in (P<0.05) in Atrai population compare to other two river populations. However, among nine meristic characters, five were showed significant differences (P<0.05) among each other. The genetic variations were analyzed with five enzymes (EST, PGM, GPI, LDH and MDH) in CA 6.1 buffer system. Two polymorphic loci Est-1* and Pgm* were interpretable in muscle with starch gel electrophoresis. The highest mean number of allele per locus was observed in the Atrai population (1.375). The mean proportion of heterozygous loci per individual was 4.305% for all populations. The average observed heterozygosity (Ho ) and expected heterozygosity (He) were 0.042 and 0.058, respectively for all the populations. The lowest pair-wise population differentiation (FST) (0.039) and the highest gene flow (Nm) (6.148) were found in the Jamuna–Brahmaputra indicating close relationship among them. In the Nei’s (1972) UPGMA dendrogram, the Jamuna and the Brahmaputra populations of L. ariza made one cluster (D=0.004) and separated from the Atrai population by the genetic distance of 0.066. The results suggest that a considerable genetic variation is existed among the natural L. ariza populations in Bangladesh.