Fat? Sick? Blame Your Grandparents’ Bad Habits
25th March 2015
Your DNA genome has “on/off” chemical switches that collectively are known as your epigenome. So your epigenome is unique and changes every time a switch is flipped. Because your epigenome’s switches are considered reversible when they are passed from parent to child, many scientists view this to be “soft evolution,” i.e., not guaranteed to be as enduring as when a mutation arises in the core DNA genome.
The epigenome can be passed on, sometimes reversed, sometimes reinforced. Unlike in classic Mendelian genetics, it is hard to predict and quantify, so you can just imagine how this variation in experimental outcomes has driven many careful, traditional scientists who believed the DNA code was the be?all and end-all of heredity completely crazy. They would try to eliminate all the variables, use genetically identical rats, and sometimes get completely different results. So it is no surprise that for decades epigenetics was ignored or pooh-poohed by funders, senior biologists, and science magazines. There was no reliable way to trace the precipitating event and no way to easily predict which individuals would be affected in future generations.
So how do our epigenomes become informed about life around us, particularly the epigenome of a fetus or a yet?to?be?conceived child? Most of the science points to our neural, endocrine, and immune systems. Our brains, glands, and immune cells sense the outside world and secrete hormones, growth factors, neurotransmitters, and other biological signaling molecules to tell every organ in the body that it needs to adapt to a changing world.