Quantitative genetics of gastrointestinal strongyle burden and associated body condition in feral horses
Gold, S; Regan, CE; McLoughlin, PD; et al.Gilleard, JS; Wilson, A; Poissant, J
Date: 6 April 2019
Journal
International Journal for Parasitology: Parasites and Wildlife
Publisher
Elsevier
Publisher DOI
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. ...
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 (h
2 = 0.43 ± 0.11), there was no evidence for
significant additive genetic variation in body condition (h
2 = 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.
Biosciences - old structure
Collections of Former Colleges
Item views 0
Full item downloads 0
Except where otherwise noted, this item's licence is described as Open access under a Creative Commons license: https://creativecommons.org/licenses/by-nc-nd/4.0/