Trypanosoma rangeli 28Sβ Ribosomal Gene Allows Intra and Interspecific Molecular Differentiation.

Trypanosoma rangeli is an avirulent flagellate protozoan that could mislead correct diagnosis of Trypanosoma cruzi infection, the causative agent of Chagas' disease, given their high similarity. Besides, T. rangeli presents two genetic groups, whose differentiation is achieved mainly by molecular approaches. In this context, ribosomal DNA (rDNA) is a useful target for intra and interspecific molecular differentiation. Analyzing the rDNA of T. rangeli and comparison with other trypanosomatid species, two highly divergent regions (Tr beta 1 and Tr beta 2) within the 28S beta gene were found. Those regions were amplified and sequenced in KP1(+) and KP1(-) strains of T. rangeli, revealing group-specific polymorphisms useful for intraspecific distinction through restriction fragment length polymorphism technique. Also, amplification of Tr beta 1 allowed differentiation between T. rangeli and T. cruzi. Tr beta 2 predicted restriction length profile, allowed differentiation between T. rangeli, T. cruzi, Trypanosoma brucei, and Leishmania braziliensis, increasing the use of Tr beta 1 and Tr beta 2 beyond a molecular approach for T. rangeli genotyping, but also as a useful target for trypanosomatid classification.