Population Genetic Structure of the Nile Tilapia (Oreochromis Niloticus) Reveled by Microsatelite DNA marker Analysis

By : Md. Golam Kibria , Afroj Jahan Sweety , Md. Samsulalam , Md. Shahidulislam

Page No: 9-19

Abstract
Information on genetic variation is essential for conservation and stock improvement programs. Three dinucleotide microsatellite loci (UNH147, UNH172 and UNH222) were analysed to reveal genetic variability in three stocks of the Nile tilapia (Oreochromis niloticus) viz. BFRI, Parbatipur, and Southampton. Upon PCR amplification, the alleles were separated on polyacrylamide gel using a sequencing gel electrophoresis system and visualized by silver-staining method. Loci UNH147 and UNH222 were polymorphic (P95) in all the populations. Differences were observed in number and frequencies of alleles as well as heterozygosities in the studied populations. The average number of allele was higher in BFRI while the average heterozygosity was higher in Parbatipur stock. BFRI population deviated from the Hardy-Weinberg expectation in all the loci, while Parbatipur and Southampton populations deviated in only one locus. None of the stock-pairs was homogeneous at any locus. The genetic distance between Parbatipur and Southampton stocks was the highest. The UPGMA dendrogram based on genetic distance resulted in two clusters: Southampton stock alone in one cluster while the remaining two stocks in the other cluster. The results reflect higher degree of genetic variability in Nile tilapia stocks available in Bangladesh compared to the Southampton stock.

Authors :
Md. Golam Kibria, Afroj Jahan Sweety and Md. Samsulalam
Department of Fisheries Biology and Genetics, Bangladesh Agricultural University, Mymensingh 2202 Bangladesh

Md. Shahidulislam
Department of Biotechnology, Bangladesh Agricultural University, Mymensingh.