Molecular Phylogenetic Characterization of Three Populations of Heterobranchus bidorsalis (Geoffroy Saint-Hilaire, 1808) from the Northeastern, Nigeria

Abstract

Heterobranchus bidorsalis (Geoffroy Saint-Hilaire, 1809) is an important species in tropical aquaculture. This study investigated the molecular phylogenetic relationships and genetic diversity of H. bidorsalis populations from three water bodies in Nigeria. Thirty fish samples (10 per location), averaging 1 kg each, were collected from Njiboliyo Reservoir, Adamawa State; Dadin Kowa Dam, Gombe State; and Lau Reservoir, Taraba State. Blood samples were collected in anticoagulant-containing EDTA bottles, and genomic DNA was extracted using the Quick-g-DNA™ MiniPrep Kit (Zymo Research, USA). The mitochondrial DNA cytochrome c oxidase (COI) gene was sequenced for all samples. Sequence analysis identified 451 conserved nucleotide positions (66.1%) and 231 variable positions (33.9%). Phylogenetic analysis showed that most individuals clustered according to their population of origin, suggesting shared maternal ancestry within populations. Genetic distances ranged from 0.000 between D6 and D5 to 0.0712 between N10 and D7. Analysis of molecular variance (AMOVA) revealed greater genetic variation among populations (62.30%) than within populations (8.5%). All pairwise FSTF{ST}FST​ values exceeded 0.070, indicating substantial population genetic structuring and potentially limited gene flow among the populations. Dadin Kowa Dam exhibited relatively high genetic diversity. These findings provide insights into the genetic differentiation and population structure of H. bidorsalis and highlight the importance of considering population-specific genetic variation in its conservation and sustainable aquaculture management.