Molecular Ecology and Evolution
Randle, April , Kalisz, Susan .
The Evolution of Reproductive Barriers among Species in the Genus Collinsia.
A critical component to understanding speciation is the knowledge of how reproductive barriers evolve and are maintained between diverging lineages. The existence and strength of reproductive barriers may also be an important factor in determining the extent to which closely related species can coexist in sympatry. Two prominent evolutionary models that predict the origin and relative strength of reproductive barriers include the Dobzhansky-Muller (D-M) model of speciation and the Reinforcement model. The D-M model predicts that the strength of reproductive isolating barriers will increase with increasing divergence time among lineages. The Reinforcement model predicts that reproductive barriers will be stronger among populations of species that co-occur (sympatry) than among populations of those same species that do not co-occur (allopatry). The genus Collinsia (Plantaginaceae) is comprised of ~22 species of self-compatible annual plants that are native to North America and often co-occur. I used an integrative biogeographic and phylogenetic approach combining greenhouse and field experiments to examine whether the presence and strength of reproductive isolating barriers among species in the genus Collinsia support the predictions of either model. My data strongly support the general prediction that isolating barriers increase with increasing divergence time. However, my data provide little support for the Reinforcement model.
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1 - University of Pittsburgh, Department of Biological Sciences, 202 Clapp Hall, Pittsburgh, PA, 15260, USA
2 - University of Pittsburgh, Department of Biological Sciences, Langley Hall, Pittsburgh, Pennsylvania, 15260, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Boulevard B/Hilton
Date: Wednesday, July 11th, 2007
Time: 10:15 AM