"Reliable chromosome segregation during cell division is absolutely critical for the survival, health and fertility of eukaryotes. In polyploids, the presence of an additional set of identical (or closely related) chromosomes makes correct segregation particularly difficult and as a result most newly formed polyploids form multivalents at metaphase I and have low fertility. By contrast, natural polyploid populations have usually evolved a highly stable meiosis with strict bivalent formation and high fertility. Recently, ASY1 was confirmed as playing an important role in this “diploidisation” of meiosis in autotetraploid Arabidopsis arenosa. ASY1 is one of several meiotic genes, mainly involved in chromosome synapsis and cohesion, that show signatures of strong selection in tetraploid A. arenosa and has also been implicated in the diploidisation of meiosis in polyploid wheat. The work outlined in this proposal will interrogate our working hypothesis that the tetraploid ASY1 variant promotes meiotic adaption in autotetraploid A. arenosa through a reduction in cross-over frequency, perhaps mediated through increased cross-over interference strength. The proposed research will also determine whether the tetraploid ASY1 variant promotes similar meiotic behaviour in other Arabidopsis species. This research will underpin an understanding of chromosome pairing and segregation that is still lacking in polyploids, and is relevant to a wide range of fields from crop improvement to cancer biology."