Genetic determinism of parasitic circadian periodicity and subperiodicity in human lymphatic filariasis.
The larval parasites of the pantropical lymphatic filariasis exhibit two types of circadian behaviour. Typically, they only appear in the human bloodstream at nighttime, synchronised with their mosquito vectors. In Polynesia and parts of Southeast Asia, free of nocturnal vectors, they are found at all hours, and each population biorhythm differs. Through a geometrical approach, we explain this circadian diversity by a single, dominant mutation: the clocks of individual parasites are set at midnight (ubiquitous) or at 2 p.m. Compared to other circadian genes, this mutation must be very old, as it is shared by four biologically remote genera of parasites. This seniority sheds new light on several theoretical and practical aspects of vector-parasite temporal relations.
Pichon
Gaston
G
Institut de recherches pour le développement (IRD), UR GEODES, 93143 Bondy cedex, France. pichon@bondy.ird.fr
Treuil
Jean-Pierre
JP
D000818:Animals; D002940:Circadian Rhythm; D004605:Elephantiasis, Filarial / Q000469:parasitology*; D033141:Genetic Determinism; D006801:Humans; D008962:Models, Theoretical; D009154:Mutation; D014958:Wuchereria bancrofti / Q000235:genetics*