Geographic range dynamics drove ancient hybridization in a lineage of angiosperms

Abstract

Factors explaining global distribution patterns have been central to biology since the 19th century, yet failure to combine dispersal-based biogeography with shifts in habitat suitability remains a present-day setback in understanding geographic distributions present and past, and time-extended trajectories of lineages. The lack of methods in a suitable integrative framework stands as a conspicuous shortcoming for reconstructing these dynamics. Here we showcase novel methods to overcome these methodological gaps, broadening the prospects for phyloclimatic modeling. We focus on a clade in the angiosperm genus Heuchera endemic to southern California that experienced ancient introgression from circumboreally distributed species of Mitella, testing hypotheses regarding biotic contact in the past between ancestral species lacking a fossil record. We obtain strong support for a past contact zone in northwestern North America, resolving this paradox of hybridization between ancestors of taxa currently separated by [~]1300 km.