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International journal for parasitology. Parasites and wildlife2019; 9; 104-111; doi: 10.1016/j.ijppaw.2019.03.010

Quantitative genetics of gastrointestinal strongyle burden and associated body condition in feral horses.

Abstract: Variability in host resistance or tolerance to parasites is nearly ubiquitous, and is of key significance in understanding the evolutionary processes shaping host-parasite interactions. While ample research has been conducted on the genetics of parasite burden in livestock, relatively little has been done in free-living populations. Here, we investigate the sources of (co)variation in strongyle nematode faecal egg count (FEC) and body condition in Sable Island horses, a feral population in which parasite burden has previously been shown to negatively correlate with body condition. We used the quantitative genetic "animal model" to understand the sources of (co)variation in these traits, and tested for impacts of an important spatial gradient in habitat quality on the parameter estimates. Although FEC is significantly heritable (  = 0.43 ± 0.11), there was no evidence for significant additive genetic variation in body condition (  = 0.04 ± 0.07), and therefore there was also no significant genetic covariance between the two traits. The negative phenotypic covariance between these traits therefore does not derive principally from additive genetic effects. We also found that both FEC and body condition increase from east to west across the island, which indicates that the longitudinal environmental gradient is not responsible for the negative phenotypic association observed between these traits. There was also little evidence to suggest that quantitative genetic parameters were biased when an individual's location along the island's environmental gradient was not incorporated into the analysis. This research provides new and important insights into the genetic basis and adaptive potential of parasite resistance in free-living animals, and highlights the importance of environmental heterogeneity in modulating host-parasite interactions in wild vertebrate systems.
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Publication Date: 2019-04-06 PubMed ID: 31011533PubMed Central: PMC6462499DOI: 10.1016/j.ijppaw.2019.03.010Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research investigates the relationship between genetic factors, parasite infections, and body conditions in feral horses of Sable Island. It found a significant heritability for parasite burden, but not body condition, indicating that genetic factors influence the susceptibility to parasites but not body condition directly.

Research Objective and Methodology

  • The research aimed at understanding the sources of variation in strongyle nematode faecal egg count (FEC) and body conditions in Sable Island horses, a feral population. The levels of these parasites have been previously observed to negatively impact the body condition of the horses.
  • The researchers used a statistical approach called an ‘animal model’ to ascertain the sources of correlation (co-variation) in these traits. They further analyzed the influence of the spatial gradient in habitat quality on the parameter estimates.

Key Findings

  • The research showed a significant heritability in FEC, represented by a heritability score of 0.43. This indicates that the genetic influence on parasite burden in these horses is substantial.
  • In stark contrast, the research found no evidence for significant additive genetic variation in body condition, signified by a low heritability score of 0.04. This suggests that genetic factors do not directly influence the horses’ body condition at a significant level.
  • Consequently, it was found that the observed negative correlation between FEC and body condition cannot be principally attributed to additive genetic effects.
  • In terms of geographic patterns, the investigation found that both FEC and body condition increase as one moves from east to west across the island. This discovery suggests that the geographical environmental gradient of the island, longitudinally, does not cause the observed negative association between FEC and body condition.

Implications of the Study

  • The study provides valuable insights into the genetic basis and adaptive potential of parasite resistance in free-living animals. It highlights the key role of environmental factors in shaping host-parasite interactions.
  • It also emphasizes that while genetic factors might predispose an animal to a higher parasitic infection, they do not significantly impact the body condition of the horses. Other elements, likely environmental, are responsible for these effects.

Cite This Article

APA
Gold S, Regan CE, McLoughlin PD, Gilleard JS, Wilson AJ, Poissant J. (2019). Quantitative genetics of gastrointestinal strongyle burden and associated body condition in feral horses. Int J Parasitol Parasites Wildl, 9, 104-111. https://doi.org/10.1016/j.ijppaw.2019.03.010

Publication

International journal for parasitology. Parasites and wildlife
ISSN: 2213-2244
NlmUniqueID: 101599824
Country: England
Language: English
Volume: 9
Pages: 104-111

Researcher Affiliations

Gold, Susannah
  • College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn, TR10 9FE, UK.
Regan, Charlotte E
  • Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.
McLoughlin, Philip D
  • Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.
Gilleard, John S
  • Department of Comparative Biology and Experimental Medicine, University of Calgary, 3280 Hospital Drive, Calgary, AB, T2N 4Z6, Canada.
Wilson, Alastair J
  • College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn, TR10 9FE, UK.
Poissant, Jocelyn
  • Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Drive, Calgary, AB, T2N 4Z6, Canada.

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Citations

This article has been cited 7 times.
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