Meeting Abstract
A central goal of evolutionary biology is understanding how genetic differentiation is accumulated and structured across genomes during lineage divergence. Recent advances in the interrogation of genome-wide patterns of variation in divergent lineages have revealed heterogenous landscapes of diversity and differentiation that are marked by genomic ‘islands’ of high population differentiation set against a genomic background of low population differentiation. Although genomic ‘islands’ are generally expected to show greater resistance to introgression, the relative contributions of various evolutionary processes to the formation of genomic ‘islands’ are poorly known. Here, we sampled genomic variation using RADseq sampling from three pairs of rattlesnake lineages, and interpreted these data using a chromosome-level reference genome for the Prairie Rattlesnake (Crotalus viridis) to compare patterns of variation, population genetic structure, and differentiation among genomic regions. Because macro-, micro-, and sex chromosomes differ in rates of recombination, we assessed each chromosome class individually. We then tested correlations between nucleotide diversity (pi), relative differentiation (Fst), and absolute differentiation (dxy) in order to infer the evolutionary processes underpinning lineage divergence. Our results illustrate the insight gained through interpreting population genetic variation using chromosomal genome assemblies, and provide links between genomic islands and the forces that contribute to their formation and persistence.
