ena-STUDY-Institute of Tropical Medicine, Antwerp-25-08-2016-09:47:50:840-44
Genome diversity of Trypanosoma congolense field isolates across 10 African countries
A key step in the fight against Animal African Trypanosomosis is to monitor the type, level and distribution of genetic diversity in natural Trypanosoma congolense populations in order to reveal the biologically relevant genomic variations that underlie pathogenesis, virulence, and drug resistance. Using Next-Generation Sequencing technology, we sequenced 52 T. congolense Savannah and four T. congolense Forest strains that differed in drug sensitivity and that were sampled between 1971 and 2014 in 10 African countries where the disease is endemic. A high density of SNPs, indels and long deletions were detected in both coding and non-coding regions, revealing a substantial amount of genetic diversity in T. congolense parasites. While most isolates were diploid, we identified one triploid sample from Burkina Faso, presenting a new kind of genome plasticity in T. congolense. In addition, we revealed complex genetic exchanges, supporting earlier findings that T. congolense parasites are recombining organisms. Interestingly, parasites collected within a short period of time and within close proximity in Zambia were genetically more diverse than parasites sampled over a period of 40 years in West, East and Central Africa that were genetically very similar. The close proximity to wildlife and the presence of the suitable vector Glossina morsitans seem to facilitate outbreeding events in Zambia, increasing the genetic diversity observed in this region.
A key step in the fight against Animal African Trypanosomosis is to monitor the type, level and distribution of genetic diversity in natural Trypanosoma congolense populations in order to reveal the biologically relevant genomic variations that underlie pathogenesis, virulence, and drug resistance. Using Next-Generation Sequencing technology, we sequenced 52 T. congolense Savannah and four T. congolense Forest strains that differed in drug sensitivity and that were sampled between 1971 and 2014 in 10 African countries where the disease is endemic. A high density of SNPs, indels and long deletions were detected in both coding and non-coding regions, revealing a substantial amount of genetic diversity in T. congolense parasites. While most isolates were diploid, we identified one triploid sample from Burkina Faso, presenting a new kind of genome plasticity in T. congolense. In addition, we revealed complex genetic exchanges, supporting earlier findings that T. congolense parasites are recombining organisms. Interestingly, parasites collected within a short period of time and within close proximity in Zambia were genetically more diverse than parasites sampled over a period of 40 years in West, East and Central Africa that were genetically very similar. The close proximity to wildlife and the presence of the suitable vector Glossina morsitans seem to facilitate outbreeding events in Zambia, increasing the genetic diversity observed in this region.