The relatively new field of epigenetics studies how trauma that our ancestors experienced can literally be passed down, attached to our DNA. An essay in a 2013 issue of Discover magazine described it: Like silt deposited on the cogs of a finely tuned machine after the seawater of a tsunami recedes, our experiences, and those of our fore-bears, are never gone, even if they have been forgotten. They become a part of us, a molecular residue holding fast to our genetic scaffolding.20
