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.

人为活动驱动的环境变化，使动物种群面临适应全新生存条件与独特威胁的挑战。过往关于生物适应性的研究多聚焦于遗传变异，然而表观遗传机制或许同样具有关键作用。DNA甲基化（DNA methylation）对疾病、毒物暴露等环境胁迫因子极为敏感，可通过调控基因表达与表型特征发挥生物学功能。本研究以入侵性体外寄生蝇下氏歪蝇（Philornis downsi）为对象，探究其对加拉帕戈斯嘲鸫（Mimus parvulus）DNA甲基化的影响：我们使用杀虫剂氯菊酯（permethrin）干预野外自由栖息的加拉帕戈斯嘲鸫巢穴中的下氏歪蝇种群，并采用简化代表性亚硫酸氢盐测序技术的衍生方法——表观基因组简化测序（epiGBS），检测寄生行为对嘲鸫雏鸟的效应。为厘清杀虫剂暴露带来的混杂效应，我们开展了配对对照实验，将圈养的斑胸草雀（Taenopygia guttata）雏鸟暴露于氯菊酯环境中。