Fil: Ghedin, Elodie. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: Bringaud, Frederic. Université Victor Segalen de Bordeaux II. Laboratoire de Parasitologie Moléculaire; Francia.Fil: Peterson, Jeremy. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: Myler, Peter. Seattle Biomedical Research Institute; Estados Unidos.Fil: Berriman, Matthew. The Wellcome Trust Genome Campus. The Wellcome Trust Sanger Institute; Inglaterra.Fil: Ivens, Alasdair. The Wellcome Trust Genome Campus. The Wellcome Trust Sanger Institute; Inglaterra.Fil: Andersson, Björn. Karolinska Institute. Center for Genomics and Bioinformatics; Suecia.Fil: Bontempi, Esteban. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Parasitología; Argentina.Fil: Eisen, Jonathan. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: Angiuoli, Sam. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: Wanless, David. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: Von Arx, Anna. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: Murphy, Lee. The Wellcome Trust Genome Campus. The Wellcome Trust Sanger Institute; Inglaterra.Fil: Lennard, Nicola. The Wellcome Trust Genome Campus. The Wellcome Trust Sanger Institute; Inglaterra.Fil: Salzberg, Steven. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: Adams, Mark D. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: White, Owen. The Wellcome Trust Genome Campus. The Wellcome Trust Sanger Institute; Inglaterra.Fil: Hall, Neil. The Wellcome Trust Genome Campus. The Wellcome Trust Sanger Institute; Inglaterra.Fil: Stuart, Kenneth. Seattle Biomedical Research Institute; Estados Unidos.Fil: Fraser, Claire M. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.Fil: El-Sayed, Najib M A. The Institute for Genomic Research. Parasite Genomics; Estados Unidos.The trypanosomatid protozoa Trypanosoma brucei, Trypanosoma cruzi and Leishmania major are related human pathogens that cause markedly distinct diseases. Using information from genome sequencing projects currently underway, we have compared the sequences of large chromosomal fragments from each species. Despite high levels of divergence at the sequence level, these three species exhibit a striking conservation of gene order, suggesting that selection has maintained gene order among the trypanosomatids over hundreds of millions of years of evolution. The few sites of genome rearrangement between these species are marked by the presence of retrotransposon-like elements, suggesting that retrotransposons may have played an important role in shaping trypanosomatid genome organization. A degenerate retroelement was identified in L. major by examining the regions near breakage points of the synteny. This is the first such element found in L. major suggesting that retroelements were found in the common ancestor of all three species.