Conti, Elena , Guggisberg, Alessia .
Primula: an ideal model system to study hybrid speciation in a species-rich, circumboreal genus.
Hybridization, often followed by polyploidization, represents one of the most important modes of speciation in plants, especially in arctic/alpine systems, probably because the repeated habitat fragmentation caused by advancing and retreating glaciers during the Pleistocene created many opportunities for secondary contact between partially differentiated populations. Primula, a circumboreal genus with high species diversity and variation of ploidy levels and breeding systems, is an ideal group to study the effects of climate change on species distribution, reproductive biology, and speciation modes at different evolutionary scales. Detailed phylogenetic analyses of Primula, sect. Aleuritia revealed that switches to polyploidy and homostyly co-occurred in the group, possibly as a result of recombination at the heterostyly linkage group caused by genomic rearrangements associated with polyploidization. The higher success of the autogamous polyploid species of sect. Aleuritia at recolonising habitats freed by glacial retreat might be explained in terms of selection for reproductive assurance. Analyses of DNA sequences from the chloroplast and nuclear genomes, in combination with chromosome in situ hybridization studies, revealed that the amphi-Beringian tetraploid P. egaliksensis evolved via inter-sectional hybridization from a North American maternal parent and an Asian paternal parent and that most ITS sequences of the tetraploid hybrid were homogenized towards the paternal repeat.
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1 - Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, Zürich, CH-8008, Switzerland
2 - Universität Zürich, Institut für Systematische Botanik, Zollikerstrasse 107, Zürich, CH-8008, Schweiz
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 28th, 2008
Time: 1:00 PM