GENETIC VARIABILITY OF NILE TILAPIA Oreochromis niloticus STRAINS AS DETERMINED BY MICROSATELLITE DNA MARKERS

Nile tilapia (Oreochromis niloticus) are originally from the Middle East and Africa and are the second most popular finfish produced in aquaculture systems. Genetic preservation of current Nile tilapia strains should be carefully conducted to prevent inbreeding, which could compromise productivity. The purpose of this study was to investigate genetic variability of Nile tilapia strains using microsatellite DNA markers; a total of nine strains have been analyzed. The analysis included DNA extraction from each fish sample and amplification using polymerase chain reaction (PCR). Nine microsatellite loci were analyzed and amplified products (microsatellite alleles) were separated by capillary electrophoresis using the Applied Biosystems™ Genetic Analyzer 3500 (Thermo Fisher Scientific). For each strain, the number of alleles, level of heterozygosity (polymorphism), frequency of genotypes, and deviation from Hardy-Weinberg Equilibrium were evaluated. Table 1 presents preliminary data on number of alleles and level of heterozygosity for microsatellite loci in Nile tilapia strains. More detailed data on intrastrain and interstrain genetic variability will be given in presentation. Based on results of this study the optimal schemes of tilapia crossing and selective breeding will be outlined.