| dc.description.abstract | Climate change may increase host-parasite interactions as temperature and precipitation levels become more favorable for parasite reproduction, survival, and transmission. Consequently, increased parasite prevalence as a result of climate change may influence the way hosts immunologically respond to parasite stressors epigenetically. Syngamus trachea is known to infect the airway epithelium of birds, but it is not known how Syngamus infection may interact with immunity on the epigenetic level. Methylation-sensitive high-resolution melt (MS-HRM) analysis was used to examine potential methylation differences in house sparrow DNA for two candidate genes: NR1D1 and CLDN22. The goals were to investigate whether relative methylation proportions of these genes were affected by infection status, fecal egg count (FEC), and age, and whether survival was affected by methylation or infection status. Linear mixed models (LMMs) were utilized controlling for experimental duplicates, island and year variation. Overall, there was very strong evidence for a difference in methylation proportion between uninfected and infected birds only for NR1D1. Infected birds showed a 64% increase in methylation for NR1D1 compared to uninfected birds. No evidence of any relationship was shown between methylation proportion and FEC for both genes. There was strong evidence for a difference in recruitment probability for NR1D1 when body condition was included. Additionally, there was moderate evidence for a difference in age only for CLDN22. These results imply that natural populations epigenetically respond to environmental stressors such as parasites, which has implications for understanding plastic responses in host-parasite interactions and hence ecological and evolutionary processes in the wild. | |