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Diversification in the S outh A merican P ampas: the genetic and morphological variation of the widespread P etunia axillaris complex ( S olanaceae)
Author(s) -
Turchetto Caroline,
Fagundes Nelson J. R.,
Segatto Ana L. A.,
Kuhlemeier Cris,
Solís Neffa Viviana G.,
Speranza Pablo R.,
Bonatto Sandro L.,
Freitas Loreta B.
Publication year - 2014
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12632
Subject(s) - biology , subspecies , coalescent theory , population , phylogeography , ecology , evolutionary biology , gene , phylogenetics , genetics , demography , sociology
Understanding the spatiotemporal distribution of genetic variation and the ways in which this distribution is connected to the ecological context of natural populations is fundamental for understanding the nature and mode of intraspecific and, ultimately, interspecific differentiation. The P etunia axillaris complex is endemic to the grasslands of southern S outh A merica and includes three subspecies: P. a. axillaris , P. a . parodii and P. a . subandina . These subspecies are traditionally delimited based on both geography and floral morphology, although the latter is highly variable. Here, we determined the patterns of genetic (nuclear and cp DNA ), morphological and ecological (bioclimatic) variation of a large number of P. axillaris populations and found that they are mostly coincident with subspecies delimitation. The nuclear data suggest that the subspecies are likely independent evolutionary units, and their morphological differences may be associated with local adaptations to diverse climatic and/or edaphic conditions and population isolation. The demographic dynamics over time estimated by skyline plot analyses showed different patterns for each subspecies in the last 100 000 years, which is compatible with a divergence time between 35 000 and 107 000 years ago between P. a. axillaris and P. a. parodii , as estimated with the IM a program. Coalescent simulation tests using A pproximate B ayesian C omputation do not support previous suggestions of extensive gene flow between P. a. axillaris and P. a. parodii in their contact zone.