The evolution of pathogenic trypanosomes.
In the absence of a fossil record, the evolution of protozoa has until recently largely remained a matter for speculation. However, advances in molecular methods and phylogenetic analysis are now allowing interpretation of the "history written in the genes". This review focuses on recent progress in reconstruction of trypanosome phylogeny based on molecular data from ribosomal RNA, the miniexon and protein-coding genes. Sufficient data have now been gathered to demonstrate unequivocally that trypanosomes are monophyletic; the phylogenetic trees derived can serve as a framework to reinterpret the biology, taxonomy and present day distribution of trypanosome species, providing insights into the coevolution of trypanosomes with their vertebrate hosts and vectors. Different methods of dating the divergence of trypanosome lineages give rise to radically different evolutionary scenarios and these are reviewed. In particular, the use of one such biogeographically based approach provides new insights into the coevolution of the pathogens, Trypanosoma brucei and Trypanosoma cruzi, with their human hosts and the history of the diseases with which they are associated.
Stevens
J R
JR
School of Biological Sciences, University of Exeter, Exeter EX4 4PS, UK. j.r.stevens@exeter.ac.uk
Gibson
W C
WC
D000349:Africa; D000818:Animals; D019143:Evolution, Molecular; D005819:Genetic Markers; D006801:Humans; D010375:Pedigree; D010802:Phylogeny; D016053:RNA, Protozoan / Q000032:analysis / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000032:analysis / Q000235:genetics; D016415:Sequence Alignment; D013020:South America; D014345:Trypanosoma / Q000145:classification / Q000235:genetics*; D014346:Trypanosoma brucei brucei / Q000145:classification / Q000235:genetics; D014349:Trypanosoma cruzi / Q000145:classification / Q000235:genetics
D005819:Genetic Markers; D016053:RNA, Protozoan; D012337:RNA, Ribosomal, 18S