Strong reinforcing selection in a Texas wildflower.
Reinforcement, the process of increased reproductive isolation due to selection against hybrids, is an important mechanism by which natural selection contributes to speciation [1]. Empirical studies suggest that reinforcement has generated reproductive isolation in many taxa (reviewed in [2-4]), and theoretical work shows it can act under broad selective conditions [5-11]. However, the strength of selection driving reinforcement has never been measured in nature. Here, we quantify the strength of reinforcing selection in the Texas wildflower Phlox drummondii using a strategy that weds a population genetic model with field data. Reinforcement in this system is caused by variation in two loci that affect flower color [12]. We quantify sharp clines in flower color where this species comes into contact with its congener, Phlox cuspidata. We develop a spatially explicit population genetic model for these clines based on the known genetics of flower color. We fit our model to the data using likelihood, and we searched parameter space using Markov chain Monte Carlo methods. We find that selection on flower color genes generated by reinforcement is exceptionally strong. Our findings demonstrate that natural selection can play a decisive role in the evolution of reproductive isolation through the process of reinforcement.
Duke Scholars
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Related Subject Headings
- Selection, Genetic
- Reproductive Isolation
- Pigmentation
- Models, Genetic
- Magnoliopsida
- Flowers
- Developmental Biology
- 52 Psychology
- 32 Biomedical and clinical sciences
- 31 Biological sciences
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Selection, Genetic
- Reproductive Isolation
- Pigmentation
- Models, Genetic
- Magnoliopsida
- Flowers
- Developmental Biology
- 52 Psychology
- 32 Biomedical and clinical sciences
- 31 Biological sciences