Origin and diversification dynamics of self-incompatibility haplotypes.
Camille E Gervais1, Vincent Castric, Adrienne Ressayre
1Laboratoire de Génétique et Evolution des Populations Végétales, Université des Sciences et Techniques de Lille, Cité Scientifique, 59655 Villeneuve d'Ascq Cedex, France.
Genetics
|April 26, 2011
Summary
Diversification of self-incompatibility (SI) genes in plants is possible in finite populations with recurrent mutations. New SI haplotypes emerge fastest when the population has fewer existing SI haplotypes.
Area of Science:
- Plant genetics
- Evolutionary biology
- Population genetics
Background:
- Self-incompatibility (SI) is a genetic system promoting outcrossing in hermaphrodite plants.
- SI involves recognition of pollen by pistils at two linked genes, preventing self-fertilization.
- The evolutionary mechanisms driving the diversification of SI alleles remain poorly understood.
Purpose of the Study:
- To investigate the conditions and dynamics of S-locus diversification.
- To understand how new self-incompatibility haplotypes evolve and increase in a population.
Main Methods:
- Analytical investigation of mutation fate in infinite populations.
- Simulations of SI haplotype evolution in finite populations with recurrent mutations.
Main Results:
- Diversification conditions are less stringent in finite populations with recurrent mutations.
- New SI haplotypes emerge more rapidly in populations with fewer existing SI haplotypes.
- Simulated allele numbers did not reach observed levels in natural plant populations.
Conclusions:
- SI diversification is feasible in panmictic populations under specific mutation and population size conditions.
- The rate of new SI haplotype emergence is inversely related to current haplotype diversity.
- Further model extensions are needed to fully explain observed S-allele diversity in plants.
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