Plant sex chromosomes defy evolutionary models | The Source | Washington University in St. Louis
Ginkgo fruits and fall leaves. (Photo: Joe Angeles/Washington University) Washington University’s glorious ginkgo allée, located just east of the John M. Olin Library, was part of the historic Cope and Stewardson plan for the campus. The ginkgo tree’s unique fan-shaped leaves turn brilliant golden yellow in fall. Renner The gingko tree is also an example of a dioecious plant: one that has either male or female flowers, not both. Such sexual specialization comes at a cost to plants. But even so, hundreds of land plant lineages have independently evolved separate sexes. Why and how th...