Molecular taxonomic identification and genetic relationships among Lutzomyia longipalpis complex and closely related species inferred from cytochrome c oxidase subunit 1

PECH-MAY, A.; MOYA, S.L.; QUINTANA, M.G.; MANTECA ACOSTA, M.; SALOMÓN, O.D.

San Cristobal, Galápagos Islands

Simposio; 10th International Symposium on Phlebotomine Sandflies; 2019

Universidad de San Francisco de Quito

Identification of the species of phlebotomine sand flies present in each focus of leishmaniasis is necessary to identify the main vectors and implement vector control strategies, similarly, the unequivocal identification of closely related species of sand flies involving vectors is highly relevant from an epidemiological viewpoint, since different species may vary in vector competence. Currently, 530 species of phlebotomine sand flies are distributed throughout North, Central and South America. In Argentina to date 38 species have been registered throughout 14 provinces. The traditional taxonomy is complex and time-consuming especially for closely related species of sand flies, furthermore, because of very subtle morphological differences between them, separation may not be possible without the use of molecular analysis. The present study examined genetic relationships and also assessed the usefulness of a 483 bp fragment of the cytochrome c oxidase I (COI) for molecular taxonomic identification among Lu. longipalpis complex and closely related species, Lu. cruzi and Lu. alencari. For the analysis, we used Genbank sequences of the mitochondrial COI gene of Lu. longipalpis, Lu. cruzi and Lu. alencari, in addition to our sequences of Lu. longipalpis from eight localities in Argentina (including sequences of the three haplogroups of Lu. longipalpis, already identified circulating in the country using ND4 and cyt b genes). Nucleotide sequences were aligned using clustal W incorporated in MEGA v.7. We used DnaSP v.5 to obtain the number of haplotypes by specie and haplotypes shared among close species using this fragment of the COI gene. Phylogenetic analysis was carried out with the Bayesian inference analysis implement with Mr. Bayes v.3.2. The Kimura 2-parameter genetic distance was estimated using the MEGA v.7. We identified 76 haplotypes, including three haplotypes shared among species: H5 y H12 shared between Lu. longipalpis (Brazil, Argentina) with Lu. cruzi (Brazil) and H59 shared between Lu. longipalpis (Brazil) with Lu. alencari (Brazil). The genetic distance K2p among species of phlebotomine sand flies was low, range between 0.025 ± 0.004 to 0.034 ± 0.005. The results suggest the inefficiency of the mitochondrial COI gene in discriminating among these closely related species, the low values of K2p genetic distance possibly can be due to introgression events in sympatric zones. These findings suggest the need to search and evaluate new molecular markers when it comes to discriminate among closely related species or species complex that probable undergone recent speciation processes.