gene with RAD51 (however, this is not the only possible mechanism, as BRCA2 variants still display some VSG switching).

In addition to homologous recombination, transcriptional regulation is also important in antigen switching, since T. brucei has multiple potential expression sites. A new VSG can either be selected by transcriptional activation of a previously silent ES, or by recombination of a VSG sequence into the active ES (see figure, "Mechanisms of VSG Switching in T. brucei").