Fine-scale genetic structure of Triatoma infestans in the Argentine Chaco

PICCINALI R. V.; GÜRTLER R. E.

Infection, Genetics and Evolution

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 34 p. 143 - 152

1567-1348

The patterns of genetic structure in naturalpopulations provide essential information for the improvement of pestmanagement strategies including those targeting arthropod vectors of humandiseases. We analyzed the patterns of fine-scale genetic structure in Triatoma infestans in a well-definedrural area close to Pampa del Indio, in the Argentine Arid-Humid Chacotransition, where a longitudinal study on house infestation and wing geometricmorphometry is being conducted since 2007. A total of 228 insects collected in16 domestic and peridomestic sites from two rural communities was genotyped for10 microsatellite loci and analyzed. We did not find departures from Hardy-Weinbergexpectations in collection sites, with three exceptions probably due to nullalleles and substructuring. Domestic sites were more variable than peridomesticsites suggesting the presence of older bug populations in domestic sites orhigher effective population sizes. Significant genetic structure was detectedusing F-statistics, a discriminant analysis of principal components and Bayesianclustering algorithms in an area of only 6.32 km2. Microsatellitemarkers detected population structuring at a finer geographic scale (180-6,300m) than a previous study based on wing geometric morphometry (> 4,000 m). Thespatial distribution of genetic variability was more properly explained by ahierarchical island than by an isolation-by-distance model. This study illustratesthat, despite more than a decade without vector control interventions enhancingdifferentiation, genetic structure can be detected in T. infestans populations, particularly applying spatial information.This supports the potential of genetic studies to provide key information forhypothesis testing of the origins of house reinfestation.