THE RELATIVE SIGNIFICANCE OF MECHANISMS OF ANTIGENIC VARIATION IN AFRICAN TRYPANOSOMES

The large number of genes involved in antigenic variation in African t rypanosomes has been the focus of a wide literature that describes an almost bewildering array of mechanisms for their differential activati on. To the outsider searching for an underlying strategy for antigenic variation, this can appear as a rather disordered and confusing pictu re. Here, David Barry argues that all understanding of which mechanism s are significant, which ones are primarily inconsequential and which ones perhaps even arise arise from overdependence on laboratory models , might be achieved by turning attention to trypanosomes that have not undergone adaptation in laboratory conditions. Application of such an approach has led to a proposal for a main mechanism for antigenic var iation.