Analysis of morphology and mitochondrial gene sequences of labeo calbasu (cypriniformes: cyprinidae) from Bangladesh

Abstract

Resolving any taxonomic unceratainty before taking appropriate conservation strategy of a species is a priority task. Status of Labeo calbasu in Bangladesh is marked as endangered. Since there exist other Labeo species in the country, unambiguous identification of Labeo calbasu is important. In this perspective, both morphology and mitochondrial gene sequences were utilized to identify the species, compare it with other related species and to study phylogeny of the group. The species were collected from Kaptai Lake, Rangamati, Chittagong. Total Genomic DNA was isolated and certain regions of mitochondrial genome were amplified through PCR technique. The PCR products were sequenced. The sequenced regions covered parts of mitochondrial 16SrRNA, ND1 and ND2, and complete sequences of three tRNA genes, i.e., tRNA , tRNA Ile Gln , tRNA Met . Multiple sequence alignment of sequenced 16SrRNA gene with two other sequences of L. calbasu from Indian subcontinent revealed 4.8% polymorphic sites. On the other hand, 19.96% polymorphic sites were detected when the sequenced region of 16SrRNA gene was aligned with nine other Labeo species, one Catla species, two Cirrhinus species and one Tor species. Similarly, sequenced regions of other genes were aligned to find intra-species and interspecies

polymorphic sites. Phylogenetic trees were also constructed to undertand relationship among the Labeo species. Overall, present work could be contributive in sustainable management of this endangered Labeo species from a conservation point of view.