The population genetics of Trypanosoma cruzi revisited in the light of the predominant clonal evolution model

Abstract

Comparing the population structure of Trypanosoma cruzi with that of other pathogens, including par-asitic protozoa, fungi, bacteria and viruses, shows that the agent of Chagas disease shares typical traitswith many other species, related to a predominant clonal evolution (PCE) pattern: statistically signif-icant linkage disequilibrium, overrepresented multilocus genotypes, near-clades (genetic subdivisionssomewhat blurred by occasional genetic exchange/hybridization) and "Russian doll" patterns (PCE isobserved, not only at the level of the whole species, but also, within the near-clades). Moreover, T. cruzipopulation structure exhibits linkage with the diversity of several strongly selected genes, with geneexpression profiles, and with some major phenotypic traits. We discuss the evolutionary significance ofthese results, and their implications in terms of applied research (molecular epidemiology/strain typing,analysis of genes of interest, vaccine and drug design, immunological diagnosis) and of experimentalevolution. Lastly, we revisit the long-term debate of describing new species within the T. cruzi taxon.