Genetic Diversity and Population Genetic Structure of a Guzerá (Bos indicus) Meta-Population

The Brazilian Guzerá population originated from a few founders introduced from India. These animals adapted well to the harsh environments in Brazil, were selected for beef, milk, or dual-purpose (beef and milk), and were extensively used to produce crossbred animals. Here, the impact of these historical events with regard to the population structure and genetic diversity in a Guzerá meta-population was evaluated. DNA samples of 744 animals (one dairy, nine dual-purpose, and five beef herds) were genotyped for 21 microsatellite loci. Ho, He, PIC, F_is, F_it, and F_st estimates were obtained considering either farms or lineages as subpopulations. Mean Ho (0.73) and PIC (0.75) suggest that genetic diversity was efficiently conserved. F_it, F_is and F_st values (95% CI) pointed to a low fixation index, and large genetic diversity: F_it (Farms = 0.021-0.100; lineages = 0.021-0.100), F_is (Farms = -0.007-0.076; lineages = -0.014-0.070), and F_st (Farms = 0.0237-0.032; lineages = 0.029-0.038). The dual-purpose herds/selection lines are the most uniform subpopulation, while the beef one preserved larger amounts of genetic diversity among herds. In addition, the dairy herd showed to be genetically distant from other herds. Taken together, these results suggest that this Guzerá meta-population has high genetic diversity, a low degree of population subdivision, and a low inbreeding level.