Should I stay or should I go now? A stochastic model of stage differentiation in Theileria annulata

The events that initiate and determine stage differentiation of protozoan p arasites are not fully understood. In this article, Brian Shiels suggests t hat for differentiation to the merozoite in Theileria annulata the process is predetermined by the parasite, but can be initiated and modulated by cha nges to the extracellular environment. Shiels proposes a mechanism operatin g on the basis of factors that regulate gene expression reaching a commitme nt threshold. Similarities across protozoan and higher eukaryotic different iation systems lend Shiels to speculate that the T. annulata model may be o f relevance to other parasites.