Mitochondrial DNAs provide insight into trypanosome phylogeny and molecular evolution

Area of Science:

• * Molecular Biology
• * Parasitology
• * Evolutionary Biology

Background:

• * Trypanosomes are single-celled parasites with unique mitochondrial DNA.
• * African livestock trypanosomes cause significant agricultural losses but are understudied.
• * The maxicircle component of mitochondrial DNA offers potential for evolutionary insights.

Purpose of the Study:

• * To explore the evolutionary history of African trypanosomes using their maxicircle DNA.
• * To assemble and analyze maxicircle mitochondrial genomes from uncharacterized trypanosome species.
• * To investigate the impact of RNA editing and gene loss on trypanosome evolution.

Main Methods:

• * Utilized long-read sequencing for complete maxicircle DNA assembly.
• * Employed published short-read data to scaffold additional gene coding regions.
• * Constructed time-resolved phylogenetic trees using maxicircle gene coding regions.

Main Results:

• * Achieved complete maxicircle assemblies for four African trypanosomes.
• * Identified conserved synteny with independent losses of Complex I genes.
• * Demonstrated significant RNA editing impact and deep phylogenetic divergences in key pathogens.

Conclusions:

• * Generated a valuable resource for trypanosome phylogeny and molecular evolution research.
• * Established a timescale for trypanosome evolution aligned with African biogeography.
• * Dated the emergence of significant human and animal pathogens like Trypanosoma brucei gambiense.