Trypanosoma vivax displays a clonal population structure

Area of Science:

• Parasitology
• Molecular Biology
• Population Genetics

Background:

• African animal trypanosomiasis (Nagana) is a significant economic burden in sub-Saharan Africa, primarily affecting livestock.
• Trypanosoma vivax is a key pathogen responsible for Nagana, transmitted by tsetse and other biting flies across Africa and South America.
• While sexual reproduction is known in related trypanosomes, its occurrence in T. vivax remains largely uninvestigated.

Purpose of the Study:

• To investigate the potential for sexual reproduction (mating) in Trypanosoma vivax.
• To understand the implications of mating for trait inheritance, such as drug resistance.
• To explore the evolutionary origins of meiosis within the Kinetoplastida order.

Main Methods:

• Genomic analysis to identify orthologues of core meiotic genes in T. vivax.
• Microsatellite marker development for T. vivax population genetics.
• Analysis of a sympatric T. vivax field population from The Gambia using these markers.

Main Results:

• Orthologues of eight core meiotic genes were identified in the T. vivax genome, suggesting a genetic potential for mating.
• Population genetic analysis of T. vivax from The Gambia revealed a clonal structure.
• Significant linkage disequilibrium, homozygote deficits, and deviations from Hardy-Weinberg equilibrium were observed at six microsatellite loci.

Conclusions:

• The presence of meiotic genes suggests T. vivax has the genetic machinery for mating.
• However, population genetic data from The Gambia indicate that mating is not occurring in this specific T. vivax population.
• This finding has implications for understanding disease dynamics and the evolution of trypanosomes.