Trypanosoma cruzi: new insights on ecophylogeny and hybridization by multigene sequencing of three nuclear and one maxicircle genes.

ABSTRACT

Natural populations of Trypanosoma cruzi are structured into five genetic lineages, T. cruzi I and T. cruzi II a to e, as the result of clonal evolution with rare genetic recombination events. To explore more in depth these phenomenons, a multigene sequencing approach was used, for the first time in the case of T. cruzi. Three nuclear loci and a maxicircle locus were sequenced on 18 T. cruzi stocks. Sequences were used to build phylogenetic trees from each locus and from concatenated sequences of all loci. The data confirmed the hybrid origin of DTUs IId and IIe, as the result of an ancient genetic recombination between strains pertaining to IIb and IIc. The data confirmed also a hybrid origin of DTUs IIa and IIc. Contrary to previous reports, we failed to detect mosaic genes. The phylogenetic relationship between DTUs and the respective roles of recombination and selection were tested.