Data from: Infection by a helminth parasite is associated with changes in DNA methylation in the house sparrow

Parasites can exert strong selective pressures on their hosts and
influence the evolution of host immunity. While several studies have
examined the genetic basis for parasite resistance, the role of
epigenetics in the immune response to parasites is less understood. Yet,
epigenetic modifications, such as changes in DNA methylation, may allow
species to respond rapidly to parasite prevalence or virulence. To test
the role of DNA methylation in relation to parasite infection we examined
genome-wide DNA methylation before and during infection by a parasitic
nematode, Syngamus trachea, in a natural population of house sparrows
(Passer domesticus) using reduced representation bisulfite sequencing
(RRBS). We found that DNA methylation levels were slightly lower in
infected house sparrows, and identified candidate genes relating to the
initial immune response, activation of innate and adaptive immunity, and
mucus membrane functional integrity that were differentially methylated
between infected and control birds. Subsequently, we used
methylation-sensitive high-resolution melting (MS-HRM) analyses to verify
the relationship between methylation proportion and Syngamus trachea
infection status at two candidate genes in a larger sample dataset. We
found that methylation level at NR1D1, but not CLDN22, remained related to
infection status, and that juvenile recruitment probability was positively
related to methylation level at NR1D1. This underscores the importance of
performing follow up studies on candidate genes. Our findings demonstrate
that plasticity in the immune response to parasites can be epigenetically
mediated, and highlight the potential for epigenetic studies in natural
populations to provide further mechanistic insight into host-parasite
interactions.