INVESTIGADORES
COSACOV MARTINEZ Andrea
congresos y reuniones científicas
Título:
Large scale phylogeographic study of the Patagonian species Calceolaria polyrhiza Cav. (Calceolariaceae)
Autor/es:
COSACOV A.; SÉRSIC A.N.; COCUCCI A.A.; SOSA V.; LEIGH J.A.
Lugar:
Vancouver, Canadá
Reunión:
Congreso; Botany 2008; 2008
Institución organizadora:
Canadian Botanical Association;Botanical Society of America;Association Botanique du Canada y otros
Resumen:
The effects of climatic changes during the Late Pleistocene and Holocene on the distribution patterns of genetic diversity in Patagonian organisms are not presently well understood. In plants, phylogeographic studies have been restricted to woody species occurring along the eastern and western forested slopes of the Andes. To our knowledge, there are no equivalent studies of plant species distributed throughout the whole Patagonian region. Here, we report our study of Calceolaria polyrhiza, a perennial herb endemic to Argentinean and Chilean Patagonia, with a primary distribution in Argentina. This species inhabits Andean forests, steppes, and coasts. Chloroplast DNA sequences of the trnH-psbA region were obtained from 369 individuals sampled from 51 localities, covering most of the species range. Nested clade phylogeographic analysis of the 31 haplotypes obtained revealed that three major clades presumably diverged by allopatric fragmentation. These clades include: 1) Andean populations located in the northern edge of the distribution (30º-35º lat S); 2) central populations (40º-48º) extending from the forest to the coast; and 3) the southern-most populations (48º-51º) from sub-Andean grasslands to the coast. At the total cladogram level, this analysis detected range expansions from possible refugia located in the central steppe, and in the south-eastern distribution range of Calceolaria polyrhiza. Genetic variation (i.e. haplotype and nucleotide diversity) decreased to the west, where populations were presumably most affected by fragmentation or extinction due to glacial activity. Our results suggest the presence of multiple refugia during glaciations and indicate a post-Pleistocene expansion of C. polyrhiza to formerly glaciated areas in Western Patagonia. We acknowledge an Nsf-Pire award (oise 0530267). AC acknowledge Red Latinoamericana de Botánica for the fellowship rlb 05-P01.