Transient SI and the dynamics of self-incompatibility alleles: a simulation model and empirical test.
A stochastic computer simulation model was created to compare the combined effects of selection and genetic drift on the dynamics of S-alleles under full sporophytic self-incompatibility (SI) versus transient SI, a form of partial SI in which flowers become self-compatible as they age. S-alleles were lost more rapidly with transient than with full SI, as is expected with weakened frequency-dependent selection. Based on these results, equilibrium S-allele diversity is expected to be lower with partial SI for populations of comparable size and migration rates. Consistent with model results, a comparison of the proportion of incompatible crosses in full diallel experiments for a fully SI and a transiently SI species in the annual genus Leptosiphon suggests that S-allele diversity is lower in the partially SI species. Results of the simulation model indicate that the transmission advantage of self-fertilization can have complex effects on S-allele dynamics in partial SI systems.
Department of Biology, East Carolina University, Howell Science Complex, Greenville, North Carolina 27858, USA. goodwilliec@ecu.edu
Carol
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Goodwillie
D000465:Algorithms; D000483:Alleles; D005075:Biological Evolution; D003198:Computer Simulation; D005799:Genes, Dominant; D017343:Genes, Plant; D005808:Genes, Recessive; D007178:Inbreeding; D008954:Models, Biological; D008957:Models, Genetic; D008962:Models, Theoretical; D010641:Phenotype; D010944:Plants / Q000235:genetics*; D012641:Selection, Genetic; D013269:Stochastic Processes