Phylogeography of two Patagonian-Fueguian mice, genus Abrothrix (Sigmodontinae).

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

Mendoza

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

IFM-SAREM

Genetic footprints can be used to assess the population history of recent species. Studies using this approach show contrasting results regarding the effect of Pleistocene glaciation on the small mammal communities of western Amazonia and North America. Not much is known for species of southern South America. Abrothrix longipilis and A. olivaceus are two species of sigmodontine rodents that inhabit the High Andes, Patagonia and Tierra del Fuego. We present preliminary results on the population genetic structure and recent historical demographic events of both species using sequences of the mitochondrial cytochrome b gene. Samples of A. olivaceus (n=108) were obtained from mainland and Fueguian localities; whereas only mainland samples of A. longipilis (n=80) were used. Genealogical and populational analyses show that in the mainland northern populations differentiate from southern populations; this pattern is stronger in A. longipilis, in which two sister mitochondrial clades are found in parapatry. In the case of A. olivaceus, two subsets of differentiated populations can be recognized, but they do not constitute distinct phylogeographic clades. Additionally, for A. olivaceus such continental populations markedly diverge from those from Tierra del Fuego. Signals of population expansion were detected in some of the continental groups. Taken as a whole, these results indicate that current genetic diversity of both species would have originated in more than one refugium, falsifying scenarios posed on previous studies. These results contribute to further our understanding of the effects of Pleistocene glaciations on mammal fauna of Patagonia.