Molecular Ecology and Evolution
Cosacov, Andrea , Sérsic, Alicia N. , Cocucci, Andrea A. , Sosa, Victoria , Johnson, Leigh A. .
Large scale phylogeographic study of the Patagonian species Calceolaria polyrhiza Cav. (Calceolariaceae).
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 (30Âº-35Âº lat S); 2) central populations (40Âº-48Âº) extending from the forest to the coast; and 3) the southern-most populations (48Âº-51Âº) 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 BotÃ¡nica for the fellowship rlb 05-P01.
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1 - Universidad Nacional de Córdoba, Laboratorio de Biología Floral - Imbiv, Velez Sarsfield 299, Córdoba, Córdoba, 5000, Argentina
2 - Instituto de Ecología, A. C., Biologia Evolutiva, Apartado Postal 63, Xalapa, Veracruz, 91000, Mexico
3 - Brigham Young University, Department of Integrative Biology, 401 Widtsoe Building, Provo, Utah, 84602, USA
Nested clade analysis.
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM