Abstract

DUQUE, María Clara; RAMIREZ, Juan David; RENDON, Lina María  and  GUHL, Felipe. Genetic variability evaluation of Trypanosoma cruzi Colombian isolates based on microsatellite DNA markers. Infect. [online]. 2011, vol.15, n.4, pp.227-234. ISSN 0123-9392.

Introduction: Chagas disease which is caused by the protozoan Trypanosoma cruzi, is a major public health problem in Latin American countries with a different distribution of the parasite across the continent in which nearly 15 million people are infected and 28 million are at risk. Genetic profiling of T. cruzi has shown great diversity and variability of the parasite allowing its classification into six discrete typing units (DTUs I-VI) in which TcII to TcVI are well characterized by different molecular markers. However, the presence of four subgroups according to the transmission cycle has only been reported in DTU T. cruzi I. Objective: To evaluate the genetic variability evidenced within TCI by the use of microsatellite markers. Materials and methods: Seven microsatellite loci were tested in fifteen Colombian isolates from vectors, reservoirs, and humans by means of PCR and automatic laser fluorescent sequencer (ALF). Data were analyzed using a population genetic data analysis software (Arlequin® 3.1 and Microsat®). Results: Variability among the isolates was demonstrated with 24 alleles, from which twelve had never been reported before. However, none of the microsatellite loci were able to support the idea of genotypes within TcI strains. The parameters of expected and observed heterozygocity allowed us to determine presence of two populations (domestic and sylvatic isolates); likewise, the linkage disequilibrium helped with the construction of two physical maps for the loci analyzed. Conclusions: We corroborated the high genetic variability displayed by TcI populations suggesting a pattern of intraspecific variation in Colombia.

Keywords : Discrete typing units; microsatellites; genotypes; Trypanosoma cruzi.

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