Incompatibility and incongruity: two different mechanisms for the non-functioning of intimate partner relationships

Abstract

A review of the literature is given to show that the hypothesis that non-functioning of the pistil-pollen relationship is solely based on the incompatibility system can no longer be maintained and that in non-functioning of the interpopulational pistil-pollen relationship/other principles are involved. A new theory regarding these principles is dealt with. The relationship between pistil and pollen is described as an intimate relationship based on matching genic systems which result from co-evolution. This theory allows two distinct mechanisms for the non-functioning of intimate partner relationships: incompatibility and incongruity. The nature, evolution, genetics and action of these mechanisms are compared. A simple letter model for matching genic systems and for incongruity in these systems is given. Applications of the new insight gained by the distinction between incompatibility and incongruity are reviewed and some consequences for research discussed. It is concluded that the influence of the S gene has been greatly overestimated, the importance of incongruity underestimated.