Genetic diversity of commercial species of the tilapia genus Oreochromis in Mexico

Abstract

Molecular techniques such as the DNA markers are commonly used to examine intra and interpopulation variation among fish strains. The objetive of this work was to analyze the genetic diversity of three tilapia species (Oreochromis aureus , O. mossambicus and O. niloticus ) cultured in Mexico, through the DNA markers, genetic and allele frequencies, number of alleles, endogamy, estimated and expected heterozygosity (He), and conformation of Hardy Weingberg, (H-W). After 150 culture days, a total of 24 individuals for each fish species were genotyped using a panel of 8 microsatellite markers. The result showed that the mean number of alleles per locus and heterozygosity for each tilapia species were 19 and 0.442, respectively. The diversity indices showed that O. aureus was more variable (He=0.813) followed by O. niloticus (HE=0.789) and O. mossambicus (HE = 0.552). Mean endogamy values fluctuated from 0.314 for O. niloticus to 0.436 for O. aureus . Highly significant deviations in most of loci of three species, and all diversity parameters suggested non-random mating in populations studied. The results in this study contribute to the knowledge of the genetic pool of the commercial tilapia species in Mexico