Development and characterization of RAPD and microsatellite markers for genetic variation analysis in the critically endangered yellow catfish Horabagrus nigricollaris (Teleostei: Horabagridae).

Random-amplified polymorphic DNA (RAPD) and microsatellite markers were developed and used for the analysis of genetic variability in the critically endangered yellow catfish Horabagrus nigricollaris, sampled from the Chalakkudy River, Kerala, India. Eight RAPD and five microsatellite markers were detected to genotype the species. In RAPD, the 73 fragments were 20.55% polymorphic, whereas 4 polymorphic loci (80%) were obtained in microsatellites. In microsatellites, the number of alleles across the 5 loci was 1-5, and the range of heterozygosity was 0.25-0.5. The mean observed number of alleles was 2.4, and the effective number was 1.775 per locus. The average heterozygosity across all investigated samples was 0.29, indicating a significant deficiency of heterozygotes in this species. RAPD and microsatellite methods report a low degree of gene diversity and lack of genetic heterogeneity in the population of H. nigricollaris, emphasizing the need for fishery management, conservation, and rehabilitation of this species.