Cytochrome Oxidase I as Tool to Evaluate the Lutzomyia longipalpis Complex: Useful Molecular Marker or Not?

In Latin America, Lutzomyia longipalpis is the principal vector of Leishmania infantum, and is associated with the majority of cases of visceral leishmaniasis. This species has distribution from southern Mexico to northern Argentina. Although widespread, its geographical distribution is discontinuous due to its low flight capacity associated with the large number of geographical barriers. Its geographic range includes climatic and environmental discontinuities that are associated with patterns of genetic divergence. In this study, a 487 bp fragment of the Cytochrome Oxidase I (COI ) mitochondrial gene was used to evaluate two sympatric populations of L. longipalpis in the municipalities from Sobral (CE-1S and 2S) and Caririaçu (CE- 1S and 2S) from Northeast, Brazil. A combination of probabilistic methods such as maximum likelihood and Bayesian Inference were applied to populations studied. Phylogenetic analysis revealed the presence of a single monophyletic clades composed of L. longipalpis morph types 1S and 2S. These results suggest that mitochondrial gene COI is not able to evaluate the genetic structure of the complex L. longipalpis.