MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
Effects of Quaternary climatic changes on the phylogeography and historical demography of the subterranean rodent Ctenomys porteousi.
MAPELLI FERNANDO; MORA MATÍAS; MIROL PATRICIA; KITTLEIN MARCELO
Journal of Zoology
Año: 2012 p. 48 - 48
The contemporary distribution of organisms cannot be understood without the knowledge of how species have responded to the geological and climatical history of the Earth. Genetic studies related to the demographic history of wildlife species can help us to elucidate the role of climate changes and other enviromental forces in shaping patterns of distribution and population structure of the species. In this work we investigated the phylogeographic pattern and historical demography of the subterranean rodent Ctenomys porteousi. We examined mitochondrial DNA control region sequences for 101 individuals collected from 7 sampling sites that cover the complete distributional range of this species. Haplotype distribution showed a significant population differentation but limited geographical structure. Genetic differentiation was not consistent with a simple model of isolation by distance, possibly evidencing a lack of equilibrium between gene flow and local genetic drift. Several independent estimates suggest that the observed phylogeographical pattern is the consequence of a complex demographic scenario. Significant population reduction and population expansion events were inferred from our data. Both kinds of demographic events showed a strong correlation with the main climatic changes that have affected the study area during the Late Pleistocene and Holocene. In particular, a strong relationship between changes in the degree of vegetation cover and population size for this rodent was infered. We therefore propose that the decrese in aridity of the Pampean region that started in the Pleistocene-Holocene boundary could have promoted a major decline in the effective population size of this species.