Population genetics of Parascaris equorum based on DNA fingerprinting.
Abstract: The large roundworm of horses, Parascaris equorum is considered ubiquitous in breeding operations, and is regarded as a most important helminth pathogen of foals. Over the past decade, this parasite has been reported increasingly resistant to anthelmintic drugs worldwide. This paper reports analysis of the population genetic structure of P. equorum. Adult parasites (n=194) collected from Sweden, Norway, Iceland, Germany, Brazil and the USA were investigated by amplified restriction fragment length polymorphism (AFLP) analysis. The genetic variation was low (Hj=0.12-0.4), for the global population of worms. This was accompanied by a weak degree of population structure (Fst=0.2), low gene flow (Nm=1.0) and low mutation rate (4 Nμ=0.07). Thus, the low genetic diversity is probably a result of a low mutation rate in DNA, although the gene flow (due to global movement of horses) is large enough to allow the spread of novel mutations. Surprisingly, isolates from Icelandic horses were not found to be different from other isolates, in spite of the fact that these have been isolated for thousands of years. The study indicates that the global P. equorum population is essentially homogenous, and continents do not appear to be strong barriers for the population structure of this species. Consequently, the potential spread of rare anthelmintic resistance genes may be rapid in a homogenous population.
Copyright © 2012 Elsevier B.V. All rights reserved.
Publication Date: 2012-11-17 PubMed ID: 23168211DOI: 10.1016/j.meegid.2012.09.022Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research paper studies the population genetics of P. equorum, a common roundworm in horses, using DNA fingerprinting. It explores how the genetic structure of P. equorum is fundamentally homogeneous worldwide and discusses the implications this has for the spread of resistances to anthelminthic drugs.
Study Object and Methodology
- This study focuses on Parascaris equorum, a widely prevalent roundworm species in the horse breeding industry. This worm is seen as a significant helminth pathogen in foals, and resistance to anthelminthic drugs is an increasing global concern.
- The researchers collected 194 adult parasites from various countries, including Sweden, Norway, Iceland, Germany, Brazil, and the United States. They then conducted an amplified restriction fragment length polymorphism (AFLP) analysis, a technique used to investigate the genetic structure and diversity within a population.
Findings
- The study found a low level of genetic variation among the global population of worms, with a weak degree of population structure. This indicates that the worm population isn’t vastly genetically different in the sampled areas.
- Despite the low mutation rate in this species, the study revealed a substantial gene flow, implying that new mutations could be spread rapidly due to the regular global movement of horses.
- Intriguingly, the study found that isolates from Icelandic horses were not genetically distinct, despite these populations having been isolated for thousands of years.
Implications
- The predominately homogeneous population genetics of P. equorum suggests that geographically separated populations are not substantial barriers to the species’ genetic structure.
- The potential for quick spread of rare anthelmintic resistance genes within a homogenous population could shed light on the worldwide increase in drug resistance and inform future strategies for managing and reducing the impact of this roundworm species.
Cite This Article
APA
Tydén E, Morrison DA, Engström A, Nielsen MK, Eydal M, Höglund J.
(2012).
Population genetics of Parascaris equorum based on DNA fingerprinting.
Infect Genet Evol, 13, 236-241.
https://doi.org/10.1016/j.meegid.2012.09.022 Publication
Researcher Affiliations
- Department of Biomedical Sciences and Veterinary Public Health, Division of Pathology, Pharmacology and Toxicology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden. eva.tyden@slu.se
MeSH Terms
- Amplified Fragment Length Polymorphism Analysis
- Animals
- Ascaridoidea / genetics
- Ascaridoidea / isolation & purification
- Brazil
- DNA Fingerprinting
- DNA, Ribosomal Spacer
- Genetic Variation
- Genetics, Population
- Germany
- Iceland
- Mutation Rate
- Norway
- Sweden
- United States
Citations
This article has been cited 8 times.- Cain JL, Nielsen MK. The equine ascarids: resuscitating historic model organisms for modern purposes. Parasitol Res 2022 Oct;121(10):2775-2791.
- Han L, Lan T, Lu Y, Zhou M, Li H, Lu H, Wang Q, Li X, Du S, Guan C, Zhang Y, Sahu SK, Qian P, Zhang S, Zhou H, Guo W, Chai H, Wang S, Liu Q, Liu H, Hou Z. Equus roundworms (Parascaris univalens) are undergoing rapid divergence while genes involved in metabolic as well as anthelminic resistance are under positive selection. BMC Genomics 2022 Jul 4;23(1):489.
- Studzińska MB, Sallé G, Roczeń-Karczmarz M, Szczepaniak K, Demkowska-Kutrzepa M, Tomczuk K. A survey of ivermectin resistance in Parascaris species infected foals in south-eastern Poland. Acta Vet Scand 2020 Jun 5;62(1):28.
- Malekpour SH, Rakhshandehroo E, Yektaseresht A. Molecular characterization of β-tubulin gene associated with benzimidazole resistance in larvae of field isolates of Parascaris (Nematoda: Ascarididae). J Parasit Dis 2019 Dec;43(4):672-678.
- Li L, Gibson DI, Zhang LP. An annotated catalogue of the ascaridoid nematode parasites of Chinese vertebrates. Syst Parasitol 2016 Jan;93(1):1-35.
- Xie Y, Zhou X, Zhang Z, Wang C, Sun Y, Liu T, Gu X, Wang T, Peng X, Yang G. Absence of genetic structure in Baylisascaris schroederi populations, a giant panda parasite, determined by mitochondrial sequencing. Parasit Vectors 2014 Dec 23;7:606.
- Nielsen MK, Wang J, Davis R, Bellaw JL, Lyons ET, Lear TL, Goday C. Parascaris univalens--a victim of large-scale misidentification?. Parasitol Res 2014 Dec;113(12):4485-90.
- Tydén E, Dahlberg J, Karlberg O, Höglund J. Deep amplicon sequencing of preselected isolates of Parascaris equorum in β-tubulin codons associated with benzimidazole resistance in other nematodes. Parasit Vectors 2014 Aug 29;7:410.
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