Escaping the immune system by DNA repair and recombination in African trypanosomes

African trypanosomes escape the mammalian immune response by antigenic variation-the periodic exchange of one surface coat protein, in the variant surface glycoprotein (VSG), for an immunologically distinct one. transcription is monoallelic, with only one being expressed at a time from a specialized locus, known as an expression site. switching is a predominantly recombination-driven process that allows sequences to be recombined into the active expression site either replacing the currently active or generating a 'new' by segmental gene conversion. In this review, we describe what is known about the factors that influence this process, focusing specifically on DNA repair and recombination.