A new Trypanosoma cruzi genotyping method enables high resolution evolutionary analyses

Area of Science:

• Molecular Biology
• Parasitology
• Genetics

Background:

• Trypanosoma cruzi is a significant human pathogen in Latin America, infecting millions.
• The parasite exhibits substantial genetic diversity across six discrete typing units (DTUs), influencing disease presentation.
• Existing genotyping methods have limitations in ease, cost, resolution, and applicability.

Purpose of the Study:

• To develop a novel molecular genotyping method for Trypanosoma cruzi.
• The method aims to utilize polymerase chain reaction (PCR) amplification of a multi-copy nuclear target combined with large-scale sequencing (LSS).

Main Methods:

• Developed the Trypanosoma cruzi Typing by Single-target Large-Scale Sequencing (TS-LSS) method.
• Applied TS-LSS to 29 T. cruzi isolates representing all known DTUs.
• Utilized PCR amplification of a single, multi-copy nuclear genome target.

Main Results:

• Successfully classified all tested T. cruzi samples to the sub-DTU level with high confidence.
• Elucidated evolutionary relationships among DTUs.
• Identified TcIII and TcIV DTUs as non-hybrid, with TcIV showing closer similarity to the ancestral type.

Conclusions:

• The TS-LSS method, requiring only one PCR reaction targeting multi-copy genes, is suitable for clinical samples with limited DNA.
• Increasing availability of large-scale sequencing technology will enhance the applicability of TS-LSS for T. cruzi genotyping.