EvSex Presentation - Tia-Lynn Ashman

Frageria provides unique insight into evolution of sex chromosomes in flowering plants - Tia-Lynn Ashman

Department of Biological Sciences
University of Pittsburgh
The secrets of sex-determination in strawberries

Sex chromosome evolution is thought to be a universal feature of separate-sexed organisms but our understanding of the process is heavily influenced by animal systems, the majority of which have ancient sex chromosomes. I will present research on species of wild strawberries (Fragaria, Rosaceae) demonstrating that plants not only provide valuable insight into the earliest stages of sex chromosome evolution from autosomes but also offer key parallels to dynamics seen at later stages in animal systems. Using comparative approach across multiple species in this young genus we have discovered at least four transitions from hermaphroditism to separate sexes, and multiple genetic avenues to loss of female function. Within the nascent ZW sex determining system we revealed novel recombination heterogeneity between the sexes, as well as geographic patterns of variation in the sex determining region that may reflect the complexity of plants with polyploid and/or hybrid histories. Thus our work is providing unique insights into the evolutionary history of sex determining regions in plants as well as separate-sexed organisms as a whole.