Epigenetic effects of environmental exposures on nestling birds

Anthropogenic changes to the environment challenge animal populations to adapt to new conditions and unique threats. While the study of adaptation has focused on genetic variation, epigenetic mechanisms may also be important. DNA methylation is sensitive to environmental stressors, such as disease and toxicant exposure, and can affect gene expression and phenotype. We studied the effects of an invasive ectoparasite, Philornis downsi, on DNA methylation of Galapagos mockingbirds (Mimus parvulus). We used the insecticide permethrin to manipulate P. downsi in nests of free-living mockingbirds and tested for effects of parasitism on nestling mockingbirds using epiGBS, a reduced-representation bisulfite sequencing approach. To distinguish the confounding effects of insecticide exposure, we ran a matching experiment exposing captive nestling zebra finches (Taenopygia guttata) to permethrin.