Molecular population genetics and phylogeography of the Chagas disease vector Triatoma infestans in South America

PICCINALI R. V., MARCET P. L., NOIREAU F., KITRON U., GÜRTLER R. E. AND DOTSON E. M.

JOURNAL OF MEDICAL ENTOMOLOGY

Entomological Society of America

Lugar: Lanham, MD, United States of America; Año: 2009 vol. 46 p. 796 - 809

0022-2585

Knowledge of the genetic variability, population structure and evolutionary history of Triatoma infestans may be useful for developing rational vector control strategies. A 661bp fragment of the mitochondrial gene COI was sequenced and analyzed in bugs from Argentina, Uruguay, Peru, and Bolivia, including peridomestic, domestic, Andean and Chaco sylvatic bugs. A total of 48 polymorphic sites among 37 haplotypes were described.  Nucleotide variation fluctuated among samples, with the highest nucleotide diversity observed in seven Argentinean Provinces. Within this group, some populations showed patterns of variability compatible with population expansions and/or fine-scale population structure while others suggested population bottlenecks and/or populations admixture processes. A maximum parsimony analysis of the haplotypes revealed the presence of a Bolivian/Peruvian and an Argentinian/Uruguayan clade. Bolivian sequences were further divided in Chaco sylvatic and Andean domestic and sylvatic. Two different nested clades were found within the Argentinian/Uruguayan cluster. AMOVA and KST* analysis supported a strong population structure in Argentina, where genetic differentiation was correlated with geographic distance. Departures from neutrality expectations and a nested cladistic analysis suggest a recent population expansion of T. infestans in Argentina, followed by restricted gene flow and patterns of isolation by distance. This expansion could have taken place as a two-wave process, as was revealed by the phylogenetic analysis and signatures of population admixture in the southernmost Argentinean populations.