Hermaphroditic organisms must balance investment into male and female reproduction and avoid conflict between these two components of fitness. My work investigates convergent origins of sex alternation in flowering plants as a window into the evolutionary and regulatory mechanisms shaping the diversity of organismal reproductive strategies.

(a) Seasonal and (b) daily systems of reciprocal sex alternation in flowering plants (heterodichogamy). Arrows represent direction of pollen movement. (c) Female and (d) male flowers of Northern California black walnut (Juglans hindsii). (e) Female- and (f) male-phase flowers of avocado (Persea americana). Photos by J.S.G.

Although species are traditionally defined as reproductively isolated groups, hybridization has recently been recognized as a common and important evolutionary process. My research investigates how evolutionary forces interact in hybrid populations to shape the distribution of hybrid ancestry in the genome and the cohesion of species in the face of gene flow.

Spatial variation of hybrid ancestry along a chromosome under different simulated evolutionary scenarios.