1. Mitochondrial DNAs provide insight into trypanosome phylogeny and molecular evolution
- Author
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Christopher Kay, Tom A. Williams, and Wendy Gibson
- Subjects
0106 biological sciences ,0301 basic medicine ,Trypanosoma ,Mitochondrial DNA ,RNA editing ,Kinetoplast ,Evolution ,maxicircle ,kinetoplast ,mitochondrial DNA ,Trypanosoma brucei ,phylogeny ,DNA, Mitochondrial ,010603 evolutionary biology ,01 natural sciences ,Trypanosome ,Evolution, Molecular ,03 medical and health sciences ,trypanosome ,Phylogenetics ,Molecular evolution ,Maxicircle ,QH359-425 ,Molecular clock ,Gene ,Ecology, Evolution, Behavior and Systematics ,Phylogeny ,biology ,biology.organism_classification ,030104 developmental biology ,Evolutionary biology ,Africa ,Research Article - Abstract
BackgroundTrypanosomes are single-celled eukaryotic parasites characterised by the unique biology of their mitochondrial DNA. African livestock trypanosomes impose a major burden on agriculture across sub-Saharan Africa, but are poorly understood compared to those that cause sleeping sickness and Chagas disease in humans. Here we explore the potential of the maxicircle, a component of trypanosome mitochondrial DNA to study the evolutionary history of trypanosomes.ResultsWe used long-read sequencing to completely assemble maxicircle mitochondrial DNA from four previously uncharacterized African trypanosomes, and leveraged these assemblies to scaffold and assemble a further 103 trypanosome maxicircle gene coding regions from published short-read data. While synteny was largely conserved, there were repeated, independent losses of Complex I genes. Comparison of pre-edited and non-edited genes revealed the impact of RNA editing on nucleotide composition, with non-edited genes approaching the limits of GC loss. African tsetse-transmitted trypanosomes showed high levels of RNA editing compared to other trypanosomes. The gene coding regions of maxicircle mitochondrial DNAs were used to construct time-resolved phylogenetic trees, revealing deep divergence events among isolates of the pathogensTrypanosoma bruceiandT. congolense.ConclusionsOur data represents a new resource for experimental and evolutionary analyses of trypanosome phylogeny, molecular evolution and function. Molecular clock analyses yielded a timescale for trypanosome evolution congruent with major biogeographical events in Africa and revealed the recent emergence ofTrypanosoma brucei gambienseandT. equiperdum, major human and animal pathogens.
- Published
- 2020