The majority of eukaryotic cells have the ability to silence genes using as regulators or triggers small non-coding RNAs. Dr. Ullu's laboratory focuses on the mechanism and biological significance of RNA interference or RNAi, whereby dsRNA triggers degradation of the corresponding target mRNA. Several years ago she and her laboratory discovered RNAi in the protozoan parasite Trypanosoma brucei, which represents one of the deepest branches of the eukaryotic lineage, and thus may give clues to the origin and evolution of RNAi. More recently, Dr. Ullu has reported the existence of a functional RNAi pathway in Leishmania Viannia braziliensis. Using a combination of reverse genetics, cell biology, and biochemistry, she is studying the mechanism and regulation of RNAi with the goals of defining the minimal set of components, unraveling the biological significance of the pathway, and how the RNAi pathway intersects with mRNA translation.