Rapid evolution of synteny associated with multiple origins of dioecy and XY sex determination

Chromosomal rearrangements are a major driver of evolutionary innovation, shaping processes including local adaptation, speciation, and sex chromosome evolution. Multispecies synteny datasets are rich in information on the drivers of genomic rearrangement, but statistical approaches that enable insights to be obtained from this information are still in their infancy. Here, we present a novel framework for the application of phylogenetic comparative methods to multispecies synteny datasets. We apply this approach to Rumex, a clade of flowering plants that exhibits rapid karyotypic evolution, including multiple origins of XY sex determination from hermaphroditic ancestors. Leveraging new genome assemblies, we find evidence for accelerated syntenic evolution associated with evolutionary transitions to dioecy, highlighting how explicit phylogenetic hypothesis testing can generate new insights into adaptive hypotheses for rearrangements.