The source for this blog is Annotating the Book of Life, by Regina Nuzza, as published by Time Magazine in their current Special Edition. Her article is on page 48.

Early on scientists asked the question: “If the DNA in each of our cells is the same, how come one cell becomes part of a hand and one becomes part of an ear.” They found the answer was that there are chemicals associated with the DNA that tell each cell how to develop. The chemicals are referred to as annotations. Interestingly, these chemicals can be modified by our behavior: what we eat; what we drink; what we smoke, inhale and even feel. Normally individual annotations last for only a day or two. Repeated annotations, what we could think of as habits, have a more prolonged effect. Let’s look at two examples.

One study of mice focused on male mice that had fatty diets. Mouse fathers that had early signs of diabetes produced pups more prone to diabetes themselves. The female mice the sired  had changes in pancreatic genes and had problems regulating insulin and glucose levels. It suggests the mouse fathers had epigenetic signatures in the sperm they produced.

Another study concerned the people of Holland who were alive during the winter of 1944, when the Nazis blockades cut down the food supply forcing them to eat tulip bulbs and grass; giving them an average of only 500 calories a day. Their children, who were conceived during this time had higher risks of obesity, heart disease and diabetes 660 years later, even though they were well fed after they were born.

This sounds like a negative outlook on our heredity and the vicissitudes of life but there is another side to the coin of epigenetics: improving the environment has a positive effect, through epigenetics, on our lives.

Next Blog: Our responsibility is to make the choices which are healthy for ourselves as well as our descendants.