The evolutionary network of whiptail lizards reveals predictable outcomes of hybridization

Hybridization between diverging lineages is associated with the generation and loss of species diversity, introgression, adaptation, and changes in reproductive mode, but it is unknown when and why it results in these divergent outcomes. We estimate a comprehensive evolutionary network for the largest group of unisexual vertebrates and use it to understand the evolutionary outcomes of hybridization. Our results show that rates of introgression between species decrease with time since divergence and suggest that species must attain a threshold of evolutionary divergence before hybridization results in transitions to unisexuality. Rates of hybridization also predict genome-wide patterns of genetic diversity in whiptail lizards. These results distinguish among models for hybridization that have not previously been tested and suggest that the evolutionary outcomes can be predictable.

Automated summary

This study estimated an evolutionary network for a group of unisexual vertebrates and found that rates of gene introgression between species decrease with time since divergence. It also revealed that a threshold level of evolutionary divergence must be reached for hybridization to result in unisexuality, and hybridization rates can predict patterns of genetic diversity in whiptail lizards.