The Evolution of Trypanosomes Infecting Humans and Primates

摘要: Based on phylogenetic analysis of 18S rRNA sequences and clade taxon composition, this paper adopts a biogeographical approach to understanding the evolutionary relationships human primate infective trypanosomes, Trypanosoma cruzi, T. brucei, rangeli cyclops. Results indicate that these parasites have divergent origins fundamentally different patterns evolution. cruzi is placed in with trypanosomes specific bats kangaroo. The predominantly South American Australian within suggest an ancient southern super-continent origin for ancestral possibly marsupials. brucei clusters exclusively mammalian, salivarian African origin, suggesting history confined Africa, while cyclops, from Asian appears evolved separately (Megatrypanum) species. Relating composition palaeogeographic evidence, divergence can be dated mid-Cretaceous, around 100 million years before present, following separation America Euramerica. Such estimate time considerably more recent than those most previous studies based molecular clock methods. Perhaps significantly, Salivarian appear, data, evolving several times faster Schizotrypanum species, factor which may contributed anomalous estimates times.