According to mitochondrial DNA evidence, Parascaris equorum and Parascaris univalens may represent the same species.
Abstract: Parascarosis is caused mainly by parasitic infections with Parascaris equorum and Parascaris univalens, the most common ascarid nematodes, in the small intestine of equines. Parascarosis often causes severe illness and even death in foals and yearlings. In this study, we obtained the complete sequence of the P. equorum mitochondrial (mt) genome and compared its organization and structure with that of P. equorum Japan isolate (nearly complete), and the complete mtDNA sequences of P. univalens Switzerland and USA isolates. The complete mtDNA genome of P. equorum China isolate is 13,899 base pairs (bp), making it the smallest of the four genomes. All four Parascaris mt genomes are circular, and all genes are transcribed in the same direction. The P. equorum mtDNA genome consists of 12 protein-coding genes, two ribosomal RNA genes, 22 transfer (t) RNA genes and one non-coding region, which is consistent with P. equorum Japan isolate and P. univalens Switzerland isolate but distinct from P. univalens USA isolate, which has 20 tRNA genes. Differences in nucleotide sequences of the four entire mt genomes range from 0.1-0.9%, and differences in total amino acid sequences of protein-coding genes are 0.2-2.1%. Phylogenetic analyses showed that the four Parascaris species clustered in a clade, indicating that P. equorum and P. univalens are very closely related. These mt genome datasets provide genetic evidence that P. equorum and P. univalens may represent the same species, which will be of use in further studies of the taxonomy, systematics and population genetics of ascarids and other nematodes.
Publication Date: 2018-05-24 PubMed ID: 29792237DOI: 10.1017/S0022149X18000330Google Scholar: Lookup
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- Journal Article
Summary
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The research paper explores the possibility that the parasitic species Parascaris equorum and Parascaris univalens, major culprits of parascarosis illness in young horses, may be one and the same based on comparison of their mitochondrial DNA sequences.
Research Objective and Method
- The aim of this study was to find out if the two common ascarid nematodes Parascaris equorum and Parascaris univalens represented the same species.
- To achieve this, the researchers sequenced the mitochondrial DNA of a Parascaris equorum China isolate, then compared it with the sequences of three other isolates: another P. equorum from Japan, and two P. univalens from Switzerland and the USA.
Results and Findings
- The P. equorum China isolate had the smallest mitochondrial genome of the four, all of which were circular and where all genes are transcribed in the same direction.
- Upon comparison, researchers found that the Chinese P. equorum, the Japanese P. equorum, and the Switzerland P. univalens all had similar mitochondrial structures. The USA P. univalens though had a distinct configuration with fewer transfer RNA genes.
- Nucleotide sequence differences among the four genomes ranged from a mere 0.1% to 0.9%, while protein-coding gene differences ranged from just 0.2% to 2.1%.
Conclusion
- The genetic similarity between the four isolates, particularly between the China and Japan P. equorum and the Switzerland P. univalens, strongly suggests that P. equorum and P. univalens may actually represent the same species.
- This conclusion is bolstered by phylogenetic analyses that show the four Parascaris species clustering together into one clade. Further research is needed to confirm this initial conclusion, and study the implications for taxonomy, systematics and population genetics of ascarids a and other nematodes.
Cite This Article
APA
Gao JF, Zhang XX, Wang XX, Li Q, Li Y, Xu WW, Gao Y, Wang CR.
(2018).
According to mitochondrial DNA evidence, Parascaris equorum and Parascaris univalens may represent the same species.
J Helminthol, 93(3), 383-388.
https://doi.org/10.1017/S0022149X18000330 Publication
Researcher Affiliations
- College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
- College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University,Daqing,Heilongjiang Province 163319,PR China.
MeSH Terms
- Animals
- Ascaridida Infections / parasitology
- Ascaridida Infections / veterinary
- Ascaridoidea / classification
- Ascaridoidea / genetics
- China
- Cluster Analysis
- Computational Biology
- DNA, Mitochondrial / chemistry
- DNA, Mitochondrial / genetics
- Equidae
- Genes, Mitochondrial
- Genetic Variation
- Horse Diseases / parasitology
- Horses
- Japan
- Phylogeny
- Sequence Analysis, DNA
- Sequence Homology
- Switzerland
- United States
Citations
This article has been cited 13 times.- Gu XH, Guo N, Chen HX, Sitko J, Li LW, Guo BQ, Li L. Mitogenomic phylogenies suggest the resurrection of the subfamily Porrocaecinae and provide insights into the systematics of the superfamily Ascaridoidea (Nematoda: Ascaridomorpha), with the description of a new species of Porrocaecum. Parasit Vectors 2023 Aug 10;16(1):275.
- Zhou M, Lu Y, Han L, Lu M, Guan C, Yu J, Liu H, Chen D, Li H, Yang Y, Zhang L, Tian L, Liu Q, Hou Z. Exploration of Parascaris species in three different Equus populations in China. Parasit Vectors 2023 Jun 15;16(1):202.
- Xie Y, Wang L, Chen Y, Wang Z, Zhu P, Hu Z, Han X, Wang Z, Zhou X, Zuo Z. The Complete Mitogenome of Toxocara vitulorum: Novel In-Sights into the Phylogenetics in Toxocaridae. Animals (Basel) 2022 Dec 15;12(24).
- Cain JL, Nielsen MK. The equine ascarids: resuscitating historic model organisms for modern purposes. Parasitol Res 2022 Oct;121(10):2775-2791.
- Souza R, Vilela RDV, Gentile R, Lopes-Torres EJ, Cordeiro-Estrela P, Moratelli R, da Costa-Neto SF, Cardoso TDS, Varella K, Maldonado Júnior A. Population genetic structure and morphological diversity of Cruzia tentaculata (Nematoda: Ascaridida), a parasite of marsupials (Didelphinae), along the Atlantic Forest on the eastern coast of South America. Parasitology 2022 Sep;149(11):1487-1504.
- Chen SY, Qiu QG, Mo HL, Gong TF, Li F, He JL, Li WC, Xie XR, Liu W. Molecular Identification and Phylogenetic Analysis of Ascarids in Wild Animals. Front Vet Sci 2022;9:891672.
- Gao JF, Mao RF, Li Y, Sun YY, Gao ZY, Zhang XG, Jin ZH, An Q, Zhang ZH, Zhang AH, Wei W, Lan Z, Wang CR. Characterization of the mitochondrial genome of Tetrameres grusi and insights into the phylogeny of Spirurina. Int J Parasitol Parasites Wildl 2022 Apr;17:35-42.
- Scala A, Tamponi C, Sanna G, Predieri G, Meloni L, Knoll S, Sedda G, Dessì G, Cappai MG, Varcasia A. Parascaris spp. eggs in horses of Italy: a large-scale epidemiological analysis of the egg excretion and conditioning factors. Parasit Vectors 2021 May 8;14(1):246.
- Urban JF Jr, Nielsen MK, Gazzola D, Xie Y, Beshah E, Hu Y, Li H, Rus F, Flanagan K, Draper A, Vakalapudi S, Li RW, Ostroff GR, Aroian RV. An inactivated bacterium (paraprobiotic) expressing Bacillus thuringiensis Cry5B as a therapeutic for Ascaris and Parascaris spp. infections in large animals. One Health 2021 Jun;12:100241.
- Abbas G, Nielsen MK, E-Hage C, Ghafar A, Beveridge I, Bauquier J, Beasley A, Wilkes EJA, Carrigan P, Cudmore L, Jacobson C, Hughes KJ, Jabbar A. Recent advances in intestinal helminth parasites of horses in the Asia-Pacific region: Current trends, challenges and future directions. Int J Parasitol Drugs Drug Resist 2025 Dec;29:100622.
- Gu XH, Mu JT, Chen HX, Li L. Integrated evidence reveals a new subspecies of the genus Seuratascaris (Nematoda: Ascaridomorpha), with characterization of the complete mitochondrial genome. Parasite 2025;32:14.
- Chen HX, Qiao HX, Zhao WT, Gu XH, Li L. Integrative evidence reveals a new species of Hysterothylacium (Nematoda: Ascaridoidea), with the characterization of its complete mitochondrial genome. Int J Parasitol Parasites Wildl 2025 Apr;26:101042.
- Sazmand A, Bahari A, Papi S, Otranto D. Parasitic diseases of equids in Iran (1931-2020): a literature review. Parasit Vectors 2020 Nov 19;13(1):586.
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