Ecological divergence and the history of gene flow in the Nearctic milksnakes (Lampropeltis triangulum complex)

Many phylogeographic studies on species with large ranges have found genetic-geographic structure associated with changes in habitat and physical barriers to gene flow. These studies may conclude absence of population structure, lineage structure that indicates unique species have been discovered, or suggest more research is needed prior to delimitation. Comparative risks of delimiting species incorrectly or failing to delimit species are usually not weighed and a more detailed return to these problems with more data often does not occur. With genomic data and better modeling capabilities we can more clearly delimit species by understanding causes of speciation with respect to biogeography and migration between lineages, the location of hybrid zones in relationship to the ecology of parental lineages, and differential introgression of genes between taxa. Here we examine the origins of three Nearctic milksnakes (Lampropeltis elapsoides, L. triangulum, and L. gentilis) using genomic-scale...