Our new paper examining genomic patterns of selection and drift in Western Diamondback Rattlesnakes was recently published in the journal Ecology and Evolution. This paper is an in-depth exploration of genomic divergence between eastern and western parental populations identified in Schield et al. 2015 MPE, and introgression across a secondary contact zone. We specifically looked for regions of the genome that have experienced selection in both processes, and tested for enrichment of candidate genes linked to divergent phenotypes between eastern and western populations.
A comparison of genomic divergence and introgression revealed a positive relationship between these processes, and there were intriguing locus-specific patterns suggesting that certain sets of genes (e.g., venom, reproduction) are important in divergence, introgression, or both. This comparison also revealed evidence of cytonuclear incompatibility leading to partial reproductive isolation of eastern and western populations.
This paper provides a genome-scale perspective on the relationships between divergence and introgression in secondary contact that is relevant for understanding the roles of selection in both generating and maintaining diversity. It also showcases use of our new method, GppFst, for detecting levels of allelic differentiation driven by selection (see related post here).
Congrats to Drew and co-authors! To read more about this study, you can download a copy from the link below:
Schield, D.R., R.H. Adams, D.C. Card, B.W. Perry, G.I.M. Pasquesi, T. Jezkova, D.M. Portik, A.L. Andrew, C.L. Spencer, E.E. Sanchez, M.K. Fujita, S.P. Mackessy, and T.A. Castoe. 2017. Insight into the roles of selection in speciation from genomic patterns of divergence and introgression in secondary contact in venomous rattlesnakes. Ecology and Evolution 7: 3951-3966. PDF.