My research focuses on understanding the evolution of reproductive isolating barriers within and among species.  I am particularly interested in understanding and identifying reproductive barriers that arise among populations within a single species, as these may represent the initial steps of divergence critical in the speciation process. 

Solanum habrochaites is a wild tomato species that exhibits a diversity of phenotypes including variation in floral size and mating system.  Shifts in the mating system from self-incompatible (SI) to self-compatible (SC) are correlated with reduced flower size and loss of S-RNase expression in northern populations.  Some SC populations of S. habrochaites show asymmetric reproductive isolation (RI) with SI populations, but this is not a general pattern.   Currently, I am working to identify the large-scale geographic pattern of RI among populations of S. habrochaites and identify the underlying genetic mechanisms that cause RI among popluations within this species.