Self-fertilization is a problem, as it leads to inbreeding. Recognition systems that prevent self-fertilization have evolved to ensure that a plant mates only with a genetically different plant and not with itself. The recognition systems underlying self-incompatibility are found all around us in nature, and can be found in at least 100 plant families and 40 percent of species. Until now, however, researchers have not known how the astonishing diversity in these systems evolves. A team of researchers at the Institute of Science and Technology Austria (IST Austria) has made steps toward deciphering how new mating types evolve in non-self recognition self-incompatibility systems, leading to the incredible genetic diversity seen in nature. The results are published in this month’s edition of Genetics.