Genetic variation of native and introduced climbing perch Anabas testudineus (Bloch, 1792) derived from mitochondrial DNA analyses

Abstract

The native and introduced Thai and Vietnamese Climbing perch Anabas testudineus are cultured in semi-intensive and intensive systems in Bangladesh. We sampled the native and the introduced A. testudineus from Bangladesh to test genetic variations based on Cytochrome C oxidase subunit I (COI) and Cytochrome (Cytb) gene. The COI nucleotide sequences of A. testudineus of India, Thailand, and Vietnam were retrieved from NCBI genebank and analyze. In the COI nucleotides, the higher AT content (53.6%) and lower GC content (46.4%) with larger differences were observed (values>0). The transition/transversion bias ( R ) based on Kimura 2-parameter (K2P) model was 8.44 with a higher transitional substitution (89%). The intraspecies genetic distance of COI nucleotide sequences based on a K2P model ranged from 0.000 to 0.094. The lowest genetic distance (0.00) was observed between the pair of reference and sequenced COI nucleotide sequences of Thai as well as Vietnamese A. testudineus , where very little genetic distance (0.002) was found between the sequenced Bangladeshi and reference Indian COI nucleotide sequences. The Thai and Vietnamese A. testudineus formed one cluster, whereas Bangladeshi and reference Indian A. testudineus formed a separate cluster in the phylogenetic tree using maximum likelihood method and time tree extrapolated from the molecular clock hypothesis. Our study provides evidence that the native and introduced A. testudineus are different lineages that might have evolved due to ecological variations at their origin. We suggest maintaining purity of breeding and cultured populations of the native and introduced A. testudineus for sustainable aquaculture in Bangladesh.