Causes and Consequences of Hybridization

The branches of the tree of life sometimes exchange material. Gene transfer via hybridization is increasingly recognized as an important source of diversification and adaptation. However, only rarely are systems sufficiently well understood to predict the degree and direction of hybridization, which limits our understanding of its causes and consequences. We have therefore experimentally studied the extent, direction, and phenotypic determinants of hybridization upon secondary contact between sub-species of the common wall lizard, Podarcis muralis. These lineages are now in contact in three different contexts: (a) in a native hybrid zone; (b) following recent introduction of one lineage into the native range of the other, and (c) in non-native populations founded by animals of both origins. We are currently finishing the first phase of this project and hope to see some papers coming out soon. The next step will be to conduct genome-wide studies of introgression using high-throughput sequencing and test predictions for how well our predictions are supported at the level of genomes in zones of secondary contact.