Data From: Estimation of genome-wide coupling in rattlesnake hybrids provides insight into the process of speciation and its progress

Genomic coupling theory predicts that progress towards speciation involves
a transition from the dominant effects of selection on individual barrier
loci to the aggregate effects of direct and indirect selection across loci
that collectively produce stronger barriers to gene flow through genetic
associations. However, our ability to test this prediction and to
understand the factors that lead to the buildup and maintenance of these
associations has been limited by a lack of methods to estimate variation
in coupling across the genome. Here we develop approaches to quantify
coupling using window-based estimates of Barton’s coupling coefficient and
apply these to a dataset of 118 genomes from a rattlesnake hybrid zone.
Our results provide empirical evidence for genomic coupling that is
consistent with the predicted relationships of coupling with
recombination, linkage, and inferences of selection. Applying these
approaches, we find evidence for coupling within and among chromosomes,
and highlight the roles of coupling in complex barrier effects, including
the Large-Z effect, cytonuclear incompatibilities, and incompatibilities
related to venom resistance. Together, our findings demonstrate the
mechanism by which coupling is predicted to lead to speciation, and
highlight how genome-wide quantification of coupling presents a promising
framework for understanding progress towards speciation and the processes
that underlie this progress.