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Updated: Mar 10, 2026
07:24
Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing
Published on: February 10, 2023
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Ascaris phylogeny based on multiple whole mtDNA genomes.
Peter Nejsum1, Mohamed B F Hawash2, Martha Betson3
1Department of Clinical Medicine, Health, Aarhus University, Denmark; Department of Veterinary Disease Biology, Faculty of Health Sciences, University of Copenhagen, Denmark.
Summary
The study reveals two distinct divergence events in Ascaris evolution, differentiating pig parasites (cluster C) early on and later splitting human-associated parasites (clusters A and B) due to human activities. This clarifies the evolutionary history of these important parasitic nematodes.
Area of Science:
- Parasitology
- Evolutionary Biology
- Genomics
Background:
- Ascaris lumbricoides (human) and Ascaris suum (pig) are parasitic nematodes with debated species status.
- Previous studies using partial cox1 gene sequences identified three main genetic clusters (A, B, C) in Ascaris from humans and pigs.
Purpose of the Study:
- To resolve the evolutionary history and species status of Ascaris by analyzing complete mitochondrial genomes.
- To investigate the divergence events shaping Ascaris populations in different hosts.
Main Methods:
- Phylogenetic analysis using whole mitochondrial genome sequences from selected Ascaris haplotypes.
- Coalescent simulations to model the evolutionary history and divergence times of Ascaris populations.
Main Results:
- Phylogenetic tree topology based on complete mitochondrial genomes mirrored previous findings from partial cox1 sequences.
- Complete mitochondrial genome analysis provided higher statistical support for internal nodes in the phylogenetic tree.
- Coalescent simulations indicated two major divergence events: an early Neolithic split leading to pig-specific cluster C, and a more recent split (~900 generations ago) creating clusters A and B, likely influenced by human dispersal.
Conclusions:
- Complete mitochondrial genome data supports distinct evolutionary trajectories for Ascaris in humans and pigs.
- The findings suggest a complex evolutionary history involving host association and human-mediated dispersal of Ascaris parasites.
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