DNA markers reveal genetic structure of Cyprinus carpio populations in River Chenab

Khalid Abbas and Saba Bashir
Department of Zoology, Wildlife and Fisheries, University of Agriculture, Faisalabad, Pakistan
Email: dr.abbas@uaf.edu.pk

Genetic variation is imperative for fish populations because it offers adaptive response to fluctuating environmental conditions. The present research work was conducted to assess allelic diversity in Cyprinus carpio populations collected from important fishing sites (30 samples from each site) of River Chenab including Marala Headworks (MHW), Qadirabad Headworks (QHW), Khanki Headworks (KHW), Trimmu Headworks (THW) and Panjnud Headworks (PHW). Five microsatellite loci (MFW-1, MFW-2, MFW-17, Barb-22 and Bgon-54) were analyzed for generating PCR based allelic data and subsequent measurement of genetic diversity parameters including allelic richness, heterozygosity, deviation from HWE, genetic differentiation and inbreeding co-efficient. All loci were found to be polymorphic. The average number of alleles ranged from 2 to 6 were observed at each locus. Mean values of Allelic richness were observed in range from 3.80 to 4.60. The average values of observed and expected heterozygosity varied between 0.4800-0.6400 and 0.7213-0.7097, respectively. The Fst values showed high level of genetic differentiation among all populations. Pairwise genetic distance (0.0231-0.2474) among all populations indicate close relationship except QHW. PHW and THW populations showed maximum level of genetic diversity. Knowledge about the allelic polymorphism of C. carpio would be helpful in resolving the issues relating to genetic conservation and effective fisheries management.

To investigate the genetic polymorphism of C. carpio populations, a total 150 samples were collected from major fishing sites of River Chenab, Pakistan. After genomic DNA extraction, 5 loci were examined for generating PCR based allelic data and subsequent measurement of various parameters of genetic polymorphism. The obtained genotypic data were subjected to statistical analyses by using various softwares. All the examined populations of C. carpio showed moderate level of polymorphism. Locus Barb-22 showed minimum (2) numbers of alleles while, locus MFW-2 and MFW-17 showed maximum (6). The highest value of Ar was observed in THW population. On the average all loci showed low level of observed heterozygosity as compared to expected heterozygosity. Based on the values of FIS the population PHW displayed maximum level of inbreeding. Natural reservoirs are most important source of fish fauna for human consumption. However, the increasing demand results to massive exploitation which ultimately cause genetic deterioration and reduce allelic diversity. The decline in fish yield due to genetic degradation has become a significant fisheries management problem that can potentially destroy the sustainability of the whole aquaculture business and the effects cannot be mitigated immediately. To prevent the loss of genetic resources of fish in wild habitat, molecular genetics research is vital for sustainable fisheries resource management.