Population characterization of three different stocks of C. catla by using microsatellite markers
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Date
2019-07
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present study was conducted to assess the genetic variation in Catla catla from three different sources, namely, the hatchery of College of Fisheries, Pantnagar, the fish farm at Sainik farm, Pattharchatta and the Baigul reservoir using well-characterized microsatellite DNA markers.
A total of 90 fin samples, 30 fish from each of the three sampling sites and seven microsatellite primers (CcatA7, CcatA12, CcatG2, Cc-1, Cc-31, Cc-40, Cc-42) showing successful amplification and polymorphism were used in the present study. Various genetic variability indices like observed and expected heterozygosity, fixation index or inbreeding coefficient, Shannon’s Information Index, AMOVA and cluster analysis were calculated by using software GenAlEx and POPGENE Version 1.32. Least observed heterozygosity as compared to the expected heterozygosity was found in Pantnagar population. Along with this, the maximum value of the coefficient of inbreeding was also observed in Pantnagar population indicating a little more level of inbreeding as compared to all the three populations. The increased amount of inbreeding in atchery stock may be due to low effective population size, hatchery breeding of farmed stock and a lack of regular germplasm exchange of appropriate genetic diversity. The heterozygosity in the reservoir stock was also found to be significantly lower than expected alike the hatchery population. The genetic variability of stock of the fish farm was however found to be moderate, which subsequently indicates a better handling and management of the fish stock by the farm managers. Shannon’s Information Index (SI) was in the optimum range for all the populations suggesting the good abundance and evenness of the species studied. AMOVA results showed that there was a low i.e. 12% but significant molecular variance among populations because of the populations representing three different sources with varied hydro-biological conditions and there was a high i.e. 85% individual variance indicating almost no impact of inbreeding on the genetic variance at the individual level. UPGMA dendogram based on Nei’s genetic distance was prepared at the end and the maximum genetic distance value was found in between the stocks of Sainik farm and Pantnagar hatchery mostly due to the distant origin of broods. However, the stocks of Baigul reservoir and
Pantnagar population were found to be more closely related with the lowest extrapolated genetic distance value giving a hint of some past parental relationship of Baigul reservoir with the stock of Pantnagar Hatchery.
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