Leaping between branches: Hybridisation and the tangled evolutionary history of true lemurs

The true lemurs (genus Eulemur) are a genetically diverse and spatially widespread group of species inhabiting most of Madagascar's forests. Including 12 recognized species, the genus can be divided into four major evolutionary groups: E. rubriventer, E. mongoz, the Brown Lemur Species Complex (BLSC), and the coronatus-macaco-flavifrons complex (CMFC), although monophyly for the CMFC is not always supported. Recent genome-based studies highlighted topological and chronological differences between nuclear and mitochondrial phylogenies of true lemurs, which could be explained by events of hybridisation. In order to reconstruct the evolutionary history of the genus, we test for gene-flow between Eulemur clades using a set of whole genome sequences representative of the diversity of the genus. Events of hybridization among true lemurs clades were identified, explaining discordances between mitochondrial and nuclear phylogenies and providing the context for mito-nuclear co-evolution, which we detected for E. rubriventer. Overall, by directly testing for hybridization among Eulemur species, we developed an evolutionary model that deepens our understanding of the unique and complex history of the genus Eulemur, and sets it as a starting point for future research.