Figure 1.

Sampling and study design. (a) Map of sampled localities, where red, blue, and black circles represent western, eastern, and admixed populations, respectively. The Continental Divide is depicted as a dashed line and the blue line represents the Pecos River. (b) Schematic view of the study design in this paper. The first steps were to estimate allelic differentiation between parental populations and genomic introgression within hybrids to identify outlier selected loci. In the lower panel, the probability of parental ancestry is compared to the hybrid index of the admixed population. Here, the dashed line represents the expectation of neutral introgression. The blue and red lines represent loci with evidence of excess eastern and western ancestry, respectively, due to the action of selection. Allelic differentiation and introgression estimates were then compared to determine whether a genomewide relationship between divergence in allopatry and admixture upon secondary contact exists, and we tested whether genes linked to outlier loci were enriched for candidate gene sets of interest