Genetic differentiation in the Patagonian-Fueguian rodents Abrothrix olivaceus and A. longipilis (Rodentia: Cricetidae).

MORA, M.; ABUD, C.; FEIJOO, M.; D'ELÍA, G.; PARDIÑAS, U.F.J.; LESSA, E.

Mendoza

Congreso; 10 International Mammalogical Congress (Mendoza, Argentina); 2009

IFM-SAREM

The Pleistocene glaciations are thought to have had a profound impact on the distribution of endemic biota both in the Northern and Southern hemispheres, leading to important changes in the historical demography and phylogeography of many species of small mammals. Here, we assess the phylogeographic patterns in the widespread species of Patagonian-Fueguian sigmodontine rodents Abrothrix olivaceus and A. longipilis, assessing if current genetic diversity have been associated to an isolation in one or more historical Patagonian refuges. We used nuclear DNA sequence data of the entire intron-7 of ?-fibrinogen (FGB-680bp) and a partial fragment of the intron-2 of alcohol dehydrogenase (ADH1-630bp) for 50 individuals of each species from 5 to 10 different populations distributed across four Argentinean provinces and one Chilean region in Patagonia. At the global level, both genetic markers showed high population substructure among different populations of A. longipilis. In contrast, A. olivaceus presented lower genetic differentiation among populations than A. longipilis, showing a polyphyletic arrangement of their haplotypes across the study area. While A. longipilis seems to be at equilibrium between mutation and genetic drift, as suggest by the Tajima’s D, A. olivaceus seems to have sufferedrecent historical population range expansions. At local level, ADH1 data support the idea of two sites as centers of population range expansions for A. olivaceus (in North Patagonia and Tierra del Fuego). Summarizing, our main finding is that phylogeographic genetic subdivision in A. olivaceus is weaker than in A. longipilis, which shows a stronger phylogeographical signal, most probably inagreement with the hypothesis of differentiation in isolation during Pleistocene climatic events. A. olivaceus shows stronger signals of historical changes in population size. The biogeography of Patagonian sigmodontines is discussed in the light of new data and novel hypotheses. Financing: NGS7813-05/CONICET-PIP6179/FONDECYT11070157.