Genetic Diversity in Farmed Nile and Red Hybrid Tilapia Stocks in India Using Microsatellite Genetic Markers

By : Karl Marx , G.C. Shyamala , G. Jeyasekaran

Page No: 131-143

Abstract
The study was carried out to asses the genetic diversity in farmed Nile and red hybrid tilapia stocks available in India using microsatellite genetic markers. Microsatellite DNA were analysed in seven different Nile tilapia (Oreochromis niloticus) (collected from Dharmapuri, Thanjavur, Sathanoor, Krishnagiri, Mangalore, Trivandrum and Vijayawada) as well as two different red hybrid tilapia (Oreochromis mossambicus X O. niloticus) (collected from Thanjavur and Vijayawada) stocks farmed in India. Microsatellite variation at nine loci (UNH106, UNH222, UNH172, UNH123, UNH216, UNH104, UNH211, UNH213 and UNH147) showed that all the nine microsatellite markers were polymorphic with mean allelic diversity ranging from 7.0 to 9.0 in Nile and 5.4 to 8.8 in red tilapia. Observed mean heterozygosity (Ho ) (value ranged from 0.663 to 0.779 in Nile tilapia and 0.759 to 0.777 in red tilapia) was lower than that of expected mean heterozygosity (He ) (value ranged from 0.777 to 0.856 in Nile tilapia and 0.792 to 0.873 in red tilapia) in all the nine population. Most of the Nile tilapia and red tilapia stocks exhibited remarkably significant homozygote excess relative to Hardy-Weinberg Equilibrium, suggesting some degree of inbreeding.

Authors :
G.C. Shyamala, K. Karalmarx and G. Jeyasekaran
Department of Fisheries Biotechnology, Fisheries College and Research Institute, Tamil Nadu Fisheries University, Thoothukudi- 628 008, Tamil Nadu, India.