Human exposure to polycyclic aromatic hydrocarbons (PAH) is a significant public health problem that will worsen with a warming climate and increased large-scale wildfires. Here we characterize an epigenetic memory at the cytochrome P450 1 A (CYP1A) gene in wild Fundulus heteroclitus that have adapted to chronic extreme PAH pollution. In wild-type fish CYP1A is highly induced by PAH. In PAH-tolerant fish CYP1A induction is blunted. Since CYP1A metabolically activates PAH this memory protects these fish from PAH-mediated cancer. However PAH-tolerant fish reared in clean water recover CYP1A inducibility indicating a non-genetic effect. Datasets herein include antibody verification chromatin immunoprecipitation CYP expression transcription factor binding sites and H3Kme1 and H3K4me mixed models.
