Genetic and haplotype diversity of redbreast tilapia (Coptodon rendalli) based on cytochrome oxidase subunit I and D-loop

Abstract

The genetic diversity in Redbreast tilapia (Coptodon rendalli) is under threat from climate change, human activities, and natural hybridisation, prompting conservation concerns. To investigate the genetic characteristics of C. rendalli, genetic diversity, genetic structure, population differentiation, and historical demography were evaluated using mitochondrial DNA COI (cytochrome oxidase subunit I) and D-loop sequences from various countries. Phylogenetic and genetic diversity analysis based on the mtDNA sequences (COI H = 9, haplogroup = 3, and D-loop H = 5, haplogroup = 3) showed private haplotypes in some of the populations. The results showed significant differences in genetic diversity among the analysed populations (P < 0.001). Molecular variance analysis showed low variation levels among populations (COIF_ST = 0.02176, D-loopF_ST = 0.52), which was significant only for D-loop. The neutrality tests and mismatch distribution based on the mtDNA supported the hypothesis of under-purifying selection of C. rendalli. The results indicated that the population did not undergo expansion. The findings of this study revealed molecular divergence among the C. rendalli populations and may serve as pivot information for the genetic improvement of this species. In conclusion, this study has elucidated the utility of two reliable and cost-effective molecular markers for analysing genetic diversity. Notably, the mitochondrial D-loop region’s sensitivity to reflecting genetic diversity in C. rendalli surpasses that of the COI gene.