Genomic Changes of Chagas Disease Vector, South America

Abstract

We analyzed the main karyologic changes that have occurred during the dispersion of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4–7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments.

Ecological host fitting of Trypanosoma cruzi TcI in Bolivia: mosaic population structure, hybridization and a role for humans in Andean parasite dispersal

“…2010) and subsequently, post‐Colombian, eastwards into Argentina, Paraguay, Uruguay and Brazil (Panzera et al . 2004; Piccinali et al . 2009).…”

Biology, diversity and strategies for the monitoring and control of triatomines - Chagas disease vectors

“…Recently, in this ever-changing epidemiologic scenario, new tools exploiting the behaviour and the genetics of T. infestans revealed that wild foci of this species may be much more widespread than previously thought. Moreover, the high genetic diversity observed in a microregion suggests that the Andean Region is the starting point for the dispersion throughout several South American countries (Noireau et al 2000, 2005, Panzera et al 2004). The increasing migration movements and current environmental changes (Briceno-Leon & Galvan 2007) could also favour new passive dispersion processes for the species and the urbanisation of the vectors.…”

Genetics and evolution of triatomines: from phylogeny to vector control

“…Interestingly, chromosomes are often marked by intraspecific polymorphism in heterochromatic content Panzera et al, 2004). For example, the Andean populations of T. infestans present a 50% higher constitutive heterochromatin content than the non-Andean populations.…”