[The intergenic region of the histone H2a gene supports two major lineages of Trypanosoma rangeli].

Introduction: Trypanosoma rangeli has been classified in the KP1(+) and KP1(-) subpopulations, based on the mini-exon gene and kinetoplast DNA minicircle amplification profiles.

Objective: The intergenic region of the histone h2a gene was compared between KP1(+) and KP1(-) strains of T. rangeli to substantiate this classification.

Materials And Methods: The amplification, cloning and sequencing of the h2a gene intergenic region was undertaken for the Tre and 5048 KP1(-) strains for comparison with the Choachí KP1(+) strain. These sequences, along with those previously reported for the KP1 (+) and KP1 (-) H14 and C23 strains, were used to reconstruct phylogenetic trees based on the "neighbor-joining", maximum parsimony and maximum likelihood methods. The Y strain of Trypanosoma cruzi was chosen as the outgroup.

Results: Intra-specific heterogeneity was observed in the size of the gene region under study, supported by bootstarp values of 85% (neighbor-joining), 66% (maximum parsimony) and 57% (maximum likelihood). The KP1(-) strains were grouped apart, clearly differentiated from the KP1(+) strains. The latter demonstrated a higher intra-specific heterogeneity, both in sequence length and composition. In addition, a closer phylogenetic relationship between T. rangeli and T. cruzi was found to be more closely related to one another than to T. rangeli and Trypanosoma brucei.

Conclusion: Phylogenetic analyses of analyzed strains based on the intergenic region of the h2a genes supported the T. rangeli grouping in two major subpopulations known as KP1(+) and KP1(-) strains. However, a higher number of strains are needed to confirm this finding.