The article provides information on a study conducted by L. M. Figueiredo, C. J. Janzen and G. A. Cross to identify the role of epigenetic regulation in the switching and immune evasion of antigen by the parasite called Trypanosoma brucei. An important first step in understanding the epigenetic regulation of antigenic variation in Trypanosoma spp. is the identification of DOT1B as a regulator of bloodstream expression site (BES) switching.