2.5 | Genetic structure and Admixture Levels
Populational structure and admixture degree were inferred using the Bayesian grouping method implemented in the STRUCTURE v 2.3.4 program (Falush et al., 2003, 2007; Pritchard et al., 2000). Parameters were calculated for each K value (1 ≤ K ≤ 6) by means of a MCMC analysis of 100,000 replicates with a burn-in period of 20,000. Results were obtained based on 25 runs per population grouping, assuming both the Admixture model, which allows individuals to have multiple population origins, and the correlated allelic frequency model (Falush et al., 2003; Pritchard et al., 2000). Finally, the posterior probability for each K value was determined by introducing the simulation results into STRUCTURE HARVESTER v 0.6.94 (Earl & vonHoldt, 2012), where K values were evaluated using the logarithm of likelihood of the observed data (LnP [D]) as well as the second order change rate of the data’s log-likelihood in distinct runs of K (ΔK) (Evanno et al., 2005).