Models of self-recognition in plants}{In flowering plants, genetically
determined systems that avoid inbreeding have evolved more than 20 times
independently. In the S-RNase gametophytic self-incompatibility system
(GSI), pollen specificity is determined by the S-locus genotype of the
haploid gametophyte. This is likely the most widespread
self-incompatibility system, since the common ancestor of about 75% of
all flowering plants possessed an /S-RNase/ based GSI. For GSI to be
maintained, the /S/-locus pistil and pollen genes must be linked and
coevolve as a genetic unit. Models aimed at describing the evolution of
such a system will be presented. At the population level, many alleles
are maintained at the S-locus by frequency dependent selection.
Population models aimed at predicting the number of alleles in
populations and their frequency spectrum will also be reviewed. |