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Dryad

Widespread reticulate evolution in an adaptive radiation

Cite this dataset

DeBaun, Dylan et al. (2023). Widespread reticulate evolution in an adaptive radiation [Dataset]. Dryad. https://doi.org/10.5061/dryad.m0cfxpp7h

Abstract

A fundamental assumption of evolutionary biology is that phylogeny follows a bifurcating process. However, hybrid speciation and introgression are becoming more widely documented in many groups. Hybrid inference studies have been historically limited to small sets of taxa, while exploration of the prevalence and trends of reticulation at deep time scales remains unexplored. We study the evolutionary history of an adaptive radiation of 109 gemsnakes in Madagascar (Pseudoxyrhophiinae) to identify potential instances of introgression. Using several network inference methods, we find twelve reticulation events within the 22-million-year evolutionary history of gemsnakes, producing 28% of the diversity for the group, including one reticulation that resulted in the diversification of an 18 species radiation. These reticulations occur at nodes with high gene tree discordance. Hybridization events occurred between north-south distributed parentals that share similar ecologies. Younger hybrids occupy intermediate contact zones between the parentals, showing that post-speciation dispersal in this group has not eroded the spatial signatures of introgression. Reticulations accumulated consistently over time, despite drops in overall speciation rates during the Pleistocene. This suggests that while bifurcating speciation may decline as the result of species accumulation and environmental change, speciation by hybridization may be more robust to these processes.

Funding

National Science Foundation, Award: DEB 1257926

National Science Foundation, Award: DEB 1257610

National Science Foundation, Award: 0641023

National Science Foundation, Award: 0423286

National Science Foundation, Award: 9984496

National Science Foundation, Award: 9625873

National Science Foundation, Award: 9322600

National Science Foundation, Award: BSR 9024505