Data from: Resistance to gapeworm parasite has both additive and dominant genetic components in house sparrows, with evolutionary consequences for ability to respond to parasite challenge

Host parasite relationships are likely to change over the coming decades
in response to climate change and increased anthropogenic stressors.
Understanding the genetic architecture of parasite resistance will aid
prediction of species’ responses to intensified parasite challenge. The
gapeworm “Syngamus trachea” is prevalent in natural bird populations and
causes symptomatic infections ranging from mild to severe. The parasite
may affect ecological processes by curtailing bird populations and is
important due to its propensity to spread to commercially farmed birds.
Our large scale dataset on an insular house sparrow metapopulation in
northern Norway includes information on gapeworm prevalence and infection
intensity, allowing assessment of the genetics of parasite resistance in a
natural system. To determine whether parasite resistance has a heritable
genetic component, we performed variance component analyses using animal
models. Resistance to gapeworm had substantial additive genetic and
dominance variance, and genome wide association studies to identify SNPs
associated with gapeworm resistance yielded multiple loci linked to immune
function. Together with genome partitioning results, this indicates that
resistance to gapeworm is under polygenic control in the house sparrow,
and likely in other bird species. Hence, our results provide the
foundation needed to study any eco-evolutionary processes related to
gapeworm infection, and show that it is necessary to use methods suitable
for polygenic and non-additive genetic effects on the phenotype.