Genetic variability among populations of Triatoma longipennis, vector of Chagas disease in western Mexico

Enzyme polymorphism in Triatoma longipennis Usinger, one of the most important vectors of Chagas disease in Mexico, was analized using starch gel electrophoresis. Seven geographic locations were sampled in order to determine gene flow among populations and to characterize intraspecific differences. Of 18 enzymes assayed, three (ES, MDH, and ME) were successfully resolved and then used to score genetic variation. ES was used to differentiate between populations. Both polymorphism and heterozygosity indicated genetic variability in the populations studied. Gene flow between some populations was found to be high. This finding and the low genetic distance between populations indicate similarity among most of the nearby localities, suggesting an important epidemiological threat.