Genomic diversity and demographic history of the Dromiciops genus (Marsupialia: Microbiotheriidae)

Three orders represent the South American fauna of marsupials. Of these, Microbiotheria was until recently known as a monotypic genus with the only surviving species Dromiciops gliroides (monito del monte). The recent proposal of a new Dromiciops species (Dromiciops bozinovici), together with new information on the origin and diversification of living microbioterians has changed the prevailing paradigm around the evolutionary history of these emblematic marsupials. Here, we used a RADseq approach to test for evidence of admixture and past or current gene flow among both species of Dromiciops and evaluate the genetic structure within D. gliroides. We analyzed 127 samples of Dromiciops distributed across the known distribution range of both species. We also inferred the joint demographic history of these lineages, thus corroborating the status of D. bozinovici as a distinct species. Demographic history reconstruction indicated that D. bozinovici diverged from D. gliroides around 4my ago and has remained isolated and demographically stable ever since. In contrast, D. gliroides is subdivided into three subclades that experienced recent expansions and moderate gene flow among them (mostly from north to south). Furthermore, genetic distances among populations within D. gliroides were significantly correlated with geographic distances. These results suggest that some of the D. gliroides populations would have survived in glacial refuges, with posterior expansions after ice retreat. Our results have important implications for the systematics of the genus and have profound conservation consequences for the new species, especially considering the fragmentation level of the temperate rainforest.Fil: Quintero Galvis, Julian F.. Universidad Austral de Chile; Chile. Millenium Institute for Integrative Biology; ChileFil: Saenz Agudelo, Pablo. Universidad Austral de Chile; ChileFil: Amico, Guillermo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Vazquez, Miriam Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Shafer, Aaron B. A.. Trent University (trent University);Fil: Nespolo, Roberto F.. Universidad Austral de Chile; Chile. Universidad Católica de Chile; Chile. Millenium Institute for Integrative Biology; Chile. Millennium Nucleus of Patagonian Limit of Life; Chil