IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Genetic differentiation in the Patagonian-fueguian rodents Abrothrix olivaceus and A. longipilis (Rodentia: Cricetidae) associated to the major Pleistocene-Holocene climatic changes: Using molecular data to the global changing assessment.
Autor/es:
MATÍAS S. MORA
Lugar:
Goa (Dona Paula, Paijim)
Reunión:
Congreso; THE PAST: A COMPASS FOR FUTURE EARTH. 4th OPEN SCIENCE MEETING; 2013
Institución organizadora:
The National Centre for Antarctic and Ocean Research (an autonomous research centre under the Ministry of Earth Sciences, Government of India), and the PAGES International Project Office
Resumen:
The biogeographic consequences of climate change have attracted considerable attention. Particularly, the ?refugial debate? centers on the possible retraction of habitats to limited areas that might have functioned as refuges for many related species, especially during glaciations of the Quaternary. One prediction of such scenarios is that populations must have experienced substantial growth accompanying climatic amelioration and the occupation of newly expanded habitats. An increasing number of phylogeographical studies in Patagonia have laid a framework for testing hypotheses concerning the impact of shifting environmental conditions on changes in the distributional ranges of the species, particularly for small mammals. Many specialists? rodent species might allow us to know how the climatic changes have limited the contraction and expansion of their populations. Assessing the phylogeographic patterns on rodent?s species, I show how the response to dramatic fluctuations in climate during the late Pleistocene-Holocene has direct implications for predicting the impact of current climate change. In order to overcome this goal I combined information derived from genetic markers and demographic studies of two species of sigmodontine Patagonian rodents, Abrothrix olivaceus and Abrothrix longipilis, which have highly extended distributional ranges into Patagonia. We used nuclear DNA sequence data of the entire intron-7 of β-fibrinogen (FGB-680bp), a partial fragment of the intron-2 of alcohol dehydrogenase (ADH1-630bp), and the entire intron of T-Complex Protein (TCP10-800bp) of 130 individuals of each species from 15-20 different populations distributed across four Argentinean provinces and two Chilean regions in Patagonia. Our goal is to supplement inferences based on mtDNA to interpret the patterns of genetic structure of these species and understand the role of glacial cycles in shaping geographical genetic variation. 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 in agreement with the hypothesis of differentiation in isolation during Pleistocene-Holocene climatic events. While A. longipilis seems to be at equilibrium between mutation and genetic drift, A. olivaceus seems to have suffered recent historical population range expansions. All intron data supported the idea of two sites as centers of population range expansions for A. olivaceus. On the other hand, A. longipilis showed distinctive ecological characteristics that appear to have limited reductions of their populations at glacial times, possibly because of its association with the Patagonian steppe (which may have expanded at glacial phases, as a result of changes in sea level). I address the value of linking population genetic inferences in these high-latitude rodent?s species with the main climatic changes observed during the Pleistocene-Holocene in Patagonia.