One hundred ways to invent the sexes: theoretical and observed paths to dioecy in plants

This review looks at the theoretical paths leading to dioecy, or the presence of separate sexes, and examines recent molecular and genomic evidence from the few plant species where those mechanisms have been uncovered. We discuss whether the evidence fits previously proposed theoretical models, and potential common mechanisms between the few known cases so far, including the role of duplication in allowing the development of new functions.