Evidence for nonallopatric speciation among closely related sympatric Heliotropium species in the Atacama Desert
Article first published online: 29 DEC 2013
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
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Ecology and Evolution
Volume 4, Issue 3, pages 266–275, February 2014
How to Cite
Ecology and Evolution 2014; 4(3):266–275
- Issue published online: 4 FEB 2014
- Article first published online: 29 DEC 2013
- Manuscript Accepted: 1 DEC 2013
- Manuscript Revised: 28 NOV 2013
- Manuscript Received: 15 AUG 2013
- Forschungskommission der Freien Universität Berlin
- EU-Programme SYNTHESYS
- Adaptive radiation;
- Heliotropium ;
The genetic structure of populations of closely related, sympatric species may hold the signature of the geographical mode of the speciation process. In fully allopatric speciation, it is expected that genetic differentiation between species is homogeneously distributed across the genome. In nonallopatric speciation, the genomes may remain undifferentiated to a large extent. In this article, we analyzed the genetic structure of five sympatric species from the plant genus Heliotropium in the Atacama Desert. We used amplified fragment length polymorphisms (AFLPs) to characterize the genetic structure of these species and evaluate their genetic differentiation as well as the number of loci subject to positive selection using divergence outlier analysis (DOA). The five species form distinguishable groups in the genetic space, with zones of overlap, indicating that they are possibly not completely isolated. Among-species differentiation accounts for 35% of the total genetic differentiation (FST = 0.35), and FST between species pairs is positively correlated with phylogenetic distance. DOA suggests that few loci are subject to positive selection, which is in line with a scenario of nonallopatric speciation. These results support the idea that sympatric species of Heliotropium sect. Cochranea are under an ongoing speciation process, characterized by a fluctuation of population ranges in response to pulses of arid and humid periods during Quaternary times.