The complete mitochondrial genome of Oxyuris equi: Comparison with other closely related species and phylogenetic implications.

The researchers conducted a comprehensive study of the mitochondrial genome of the equine pinworm, Oxyuris equi. They compared this genome structure with those of other pinworm species, highlighting genetic similarities and differences which contribute to our understanding of pinworm evolution.

Study Overview

• This research focused on the complete mitochondrial genome of the equine pinworm, Oxyuris equi, which is regarded as the most prevalent horse nematode causing major economic losses.
• The researchers sequenced the pinworm’s mitochondrial (mt) genome and compared it to those of related pinworm species (Enterobius vermicularis and Wellcomia siamensis).

Results: Genome Structure

• The O. equi’s mitochondrial genome is a 13,641-bp circular DNA molecule that encodes 36 genes (12 protein-coding genes, 22 tRNAs, two rRNAs), and one non-coding region.
• Compared to E. vermicularis and W. siamensis, O. equi’s genome is slightly shorter.
• The gene arrangement observed was consistent with that of GA13-type E. vermicularis, but differed from GA12-type W. siamensis.

Phylogenetic Analysis

• Researchers used maximum parsimony, maximum likelihood, and Bayesian inference computational algorithms to conduct phylogenetic analysis using concatenated amino acid sequences of the 12 protein-coding genes.
• Within the family of Chromadorea nematodes, two distinct clades were identified. One clade was formed by Spiruromorpha, while Rhabditomorpha, Ascaridomorpha, and Oxyuridomorpha formed another clade.
• O. equi, E. vermicularis, and W. siamensis were found to represent distinct but closely related species, thus indicating that Oxyuridomorpha is paraphyletic.

Implications

• The completion of the O. equi mitochondrial genome sequencing contributes to studies on the molecular epidemiology and population genetics of pinworms – it provides new genetic markers for this purpose.
• The results illuminate the evolutional relationship between different types of nematodes, providing valuable insights for further research on the control and prevention of diseases caused by these parasites.