Testing the central margin hypothesis into a phylogeographical framework in the Patagonian plant Calceolaria polyrhiza.

COSACOV, A.; SÉRSIC, A. N.; JOHNSON, L.; SOSA, V.; COCUCCI, A. A.

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Congreso; VI Southern Connection Congress. Gondwana reunited: A Southern perspective for a changing world.; 2010

Southern Connection Comitee

Testing the central-margin hypothesis into a phylogeographical framework in thePatagonian plant Calceolaria polyrhizaCOSACOV A.* (1); SéRSIC A. (2); JOHNSON L. (3); SOSA V. (4) and COCUCCI A.A.(1) Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET-Universidad Nacional de Córdoba (2)Instituto Multidisciplinario de Biología Vegetal  (3) Department of Integrative Biology, BYU, USA (4)Instituto de Ecología, A. C., Xalapa, México *andreacosacov@gmail.comUnderstanding the patterns and processes associated with geographical variation in population geneticand phenotypic structure across a species range is motivated by conservation concerns and constitutesan important issue in evolutionary ecology. Recent reviews provide weak support to the acceptedcentral-margin model. This could be the result of a preponderant effect of historical events indetermining range-wide genetic structure. However, almost no study has incorporated aphylogeographical framework; therefore we report our phylogeographical study of Calceolaria polyrhiza, a perennial herb endemic to Patagonia, for the evaluation of this hypothesis. We used cpDNA sequencesfrom 590 individuals sampled from 68 localities, in the Andean forests and Patagonian steppes, coveringall the species range. We tested the central-margin hypothesis at the whole species level and at differentlevels of the genealogy, using the geographically bounded, monophyletic lineages within the species, asindependent replicates. We analyzed the geographic structure of genetic and phenotypic (i.e. variationcoefficient of 14 functional phenotypic traits) variability. In general, at lower levels of the genealogyresults support the central-margin hypothesis while at higher levels the effect of allopatric fragmentation,secondary contact and Pleistocene refugia dilute these patterns. The associated geographical trends inneutral and quantitative phenotypic trait variation are also discussed.