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).