Evidence for a neotropical origin of Leishmania

Contradictory biogeographic hypotheses for either a Neotropical or a Palaea rctic origin of the genus Leishmania have been proposed. Hypotheses constru cted on the basis of biogeographic data must be tested against an independe nt dataset and cannot be supported by biogeographic data alone. In the abse nce of a fossil record for the Leishmania these two hypotheses were tested against a combined dataset of sequences from the DNA polymerase A catalytic subunit and the RNA polymerase II largest subunit. The phylogeny obtained provided considerable support for a Neotropical origin of the genus Leishma nia and leads us to reject the hypothesis for a Palaearctic origin.