On the evolutionary history of the circumsporozoite protein in plasmodia.

We report the complete nucleotide sequence of the circumsporozoite (CS) gene of Plasmodium brasilianum and present an analysis of its evolutionary profile. Despite the lack of a reliable time scale, the analysis of the number and distribution of fixations among seven taxa provides a first glimpse of the evolutionary history of the CS gene, and suggests that the branching events of this gene are completely unconnected with--and far precede in time--the speciation event of the parasite's vertebrate hosts.