Morphometric and genetic characterization of cultured and wild populations of tilapia, Oreochromis niloticus in India

To study genetic variation in Indian populations of tilapia, Oreochromis niloticus, both truss morphometrics and genetic characterization have been performed. In the present study, 88 individuals from two farm populations (GIFT and West Bengal) and one reservoir population (Gujarat) were selected to analyse variations at ten morphometric landmarks and eight microsatellite loci. Truss morphometric analysis showed PCI, PCII, and PCIII expressing 29.1%, 21.36%, and 15.48% of the variance, respectively. Results showed no clear shift in shape between the studied populations of O. niloticus, indicating low morphological variability among them. The number of microsatellite alleles ranged from 3 to 9, while expected heterozygosity (HE) and observed heterozygosity (HO) values ranged from 0.56 (WB) to 0.68 (Guj) and 0.59 (GIFT) to 0.72 (Guj), respectively. The Gujarat and West Bengal populations had the smallest pairwise distance (0.0123) between them, indicating that they were genetically closer. Individuals from GIFT, however, showed the largest distance from the other populations. DNA marker variations revealed the highest genetic variability in the Gujarat population and the lowest variability in the GIFT population. The results of this study will help establish a base population for genetic improvement program and conservation of wild populations.