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.