Identification of six Trypanosoma cruzi phylogenetic lineages by random amplified polymorphic DNA and multilocus enzyme electrophoresis

Genetic characterisation of Trypanosoma cruzi variants is of foremost importance, due to considerable genetic and biological heterogeneity in the parasite populations. Two major phylogenetic lineages, each highly heterogeneous, have been previously described within this species. Here we characterised a geographically and ecologically diverse sample of stocks representative of the breadth of the known clonal diversity of each major lineage, using random amplified polymorphic DNA with 20 primers and multilocus enzyme electrophoresis at 22 loci. Molecular hybridisation experiments were performed to control the homology of randomly amplified DNA markers. Both sets of data were highly consistent and supported the existence of two major lineages. Additionally, we found that lineage 2 appeared further partitioned into five sharply delineated phylogenetic clusters, each comprising one of the following reference strains: CanIII c11 (Z3 reference), M5631 c15, Esmeraldo c13 (22 reference), CL Brener, and MN c12. The two first clusters were found mainly in sylvatic environments, whereas the three latter were restricted to domestic transmission cycles and were only collected South to the Amazon Basin. In contrast, lineage 1, which included Miles Z1 reference strain X10 c11, was not Further subdivided and was encountered across the entire endemic area, in both domestic and sylvatic cycles. Thus. T. cruzi appeared to be subdivided into six discrete typing units, or DTUs, exhibiting distinct geographic and ecological ranges. Reliable diagnostic markers for the two major lineages and the five smaller DTUs of lineage 2 are described, and correspondence with previous classifications of T. cruzi genotypes is given in order to help communication on T. cruzi phylogenetic diversity. (C) 2000 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.