Self fertilisation and inbreeding can lead to a loss of fitness due to reduced genetic diversity at the scale of both the organism and the population. However in the short term, individuals that don't try and avoid inbreeding leave more offspring simply because they don't reject any potential mates. These two contrasting selection effects set the stage for a battle between self compatible (inbreeding) vs self incompatible (outbreeding) alleles. In nature around half the hermaphroditic plants and animals show a mixture of both outcrossing and selfing.(Jarne and Auld 2007) An enormous amount of theoretical work has already been done in this field to try and tease apart what selective forces can maintain the observed distributions in  nature; the proposed explanations include mutation load, varying natural selection, and heterozygote advantage among others.

Using a single stochastic simulation framework, I have compared the effects of various proposed slection criteria and have used the extracted parameters to predict which selection criteria are more likely to be the true factors driving the prevalence of mixed self incompatibility in nature.

The most prevalent and well studied self incompatibility system in plants is the 1-locus gametophytic self incompatibility(GSI) system. Multi locus GSI systems are both rare and the forces acting on them are not well studied. I will present some predictions on the evolution of Multi locus GSI systems."