My research program is focused on the study of Entamoeba histolytica, a medically important parasite with an interesting evolutionary niche. Significant morbidity and mortality are caused by amebic infection with the majority of disease in underdeveloped and resource-poor countries. Despite its global importance, this organism is significantly understudied and little is known about the molecular basis of pathogenesis, stage conversion, or gene expression. Furthermore, E. histolytica is an early branching eukaryote, and thus occupies an interesting evolutionary niche, which provides insights into multiple aspects of eukaryotic evolution. The goals of our lab are to investigate the molecular basis of pathogenesis from a broad perspective. Thus we ask: what makes these parasites able to invade the host and cause disease, how do the parasites survive long-term in the host, does the interaction between the host and parasite influence parasite virulence, and how can evolutionary and epidemiological trends help us understand disease pathogenesis. Our findings are important for the study of this pathogen (to develop novel tools for diagnostics, treatment, and vaccine approaches), but also have important implications for the broader questions of the molecular basis of host-pathogen interactions. Important contributions of our work include dissecting the developmental pathway in this organism as well as identification of a novel gene regulatory mechanism by unusual subsets of small RNAs.