RT Journal Article SR Electronic T1 Maxicircle architecture and evolutionary insights into Trypanosoma cruzi complex JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.05.11.443566 DO 10.1101/2021.05.11.443566 A1 Luisa Berná A1 Gonzalo Greif A1 Sebastián Pita A1 Paula Faral-Tello A1 Florencia Díaz-Viraqué A1 Rita De Cássia Moreira De Souza A1 Gustavo Adolfo Vallejo A1 Fernando Alvarez-Valin A1 Carlos Robello YR 2021 UL http://biorxiv.org/content/early/2021/05/11/2021.05.11.443566.abstract AB We sequenced maxicircles from T. cruzi strains representative of the species evolutionary diversity by using long-read sequencing, which allowed us to uncollapse their repetitive regions, finding that their real lengths range from 35 to 50 kb. T. cruzi maxicircles have a common architecture composed of four regions: coding region (CR), AT-rich region, short (SR) and long repeats (LR). Distribution of genes, both in order and in strand orientation are conserved, being the main differences the presence of deletions affecting genes coding for NADH dehydrogenase subunits, reinforcing biochemical findings that indicate that complex I is not functional in T. cruzi. Moreover, the presence of complete minicircles into maxicircles of some strains lead us to think about the origin of minicircles. Finally, a careful phylogenetic analysis was conducted using coding regions of maxicircles from up to 29 strains, and 1023 single copy nuclear genes from all of the DTUs, clearly establishing that taxonomically T. cruzi is a complex of species composed by group 1 that contains clades A, B and D, and group 2 containing clade C. No significant differences were found in hybrid strains that justify the existence of TcV and Tc VI as separate clades: our results indicate that a unique event of hybridization between TcII and TcIII occurred. Three variants of maxicircles exist in T. cruzi: a, b and c, in correspondence with clades A, B, and C from mitochondrial phylogenies. While A and C carry maxicircles a and c respectively, both clades B and D carry b maxicircle variant; hybrid strains also carry the b- variant. We then propose a new nomenclature that is self-descriptive and makes use of both the phylogenetic relationships and the maxicircle variants present in T. cruzi.Competing Interest StatementThe authors have declared no competing interest.