Assessment of genetic diversity among wild and captive-bred Labeo rohita through microsatellite markers and mitochondrial DNA

Abstract

Genetic diversity serves as the basis for selecting and genetically enhancing any culturable species in aquaculture. Here, two different strains of wild (River Ravi and River Kabul) and six captive-bred strains of Labeo rohita from various provinces were selected, and genetic diversity among them was evaluated using three different microsatellite markers, i.e., Lr-28, Lr-29, and Lr-37, and one mitochondrial CO1 (Cytochrome c oxidase subunit 1) gene. Different strains of L. rohita were collected, and part of their caudal fin was cut and preserved in ethanol for DNA extraction and determination of genetic diversity among them. Results indicated that selected markers were polymorphic with polymorphic information content (PIC) content values above 0.5 with the highest in Lr-28 followed by Lr-29 and then Lr-37. The observed heterozygosity (Ho) of all strains was higher (Avg: 0.731) but less than the expected heterozygosity (He). Moreover, TMs and WRs showed the highest He, while TKs showed the lowest, He. Overall, inbreeding coefficient (FIS) values observed for all strains with selected markers were positive. The DNA barcoding with the CO1 gene revealed genetic variation among various strains, as demonstrated by the clades in the phylogenetic tree separating the strains into two distinct clusters that then divided into sub-clusters. In conclusion, TMs showed the highest heterozygosity as compared to other strains. Overall results provide the baseline data for the initiation of the genetic improvement program.