Today I’m introducing epigenetics, a subject that will soon be added to our list of scientific and ethical debates. Few of us know the word or its meaning, but this emerging branch of science already affects our lives in many ways.
We know that genetic makeup inherited from our parents and nurture provided by families and society are powerful influences on our development. Epigenetics has demonstrated that environmental factors continuously adjust how our genes affect us. Ethical and legal questions will arise as we learn to manipulate how genes are expressed. Before those discussions begin, we’ll need to understand the possibilities that may unfold.
Every cell in an organism contains the same genes but natural epigenetic stimuli tell cells in a fetus to differentiate into skin, eyes and so forth. Many kinds of internal and external events can stimulate genes to activate or deactivate. External factors including nutrition, stress, climate and chemicals have been demonstrated to cause epigenetic change. In some cases this creates identifiable “tags” on genes.
We have long known that taking certain chemicals into our bodies can cause cancer, addiction, and other health problems but we didn’t understand how it happened. Now it appears that epigenetic change can cause of some kinds of cancer, diabetes and other illnesses. There are also adaptive and useful epigenetic changes. Here are some examples.
In rat colonies with a safe environment and plentiful food, baby rats (called pups) that have attentive mothers who lick and groom them a lot tend to mature as calm, relaxed adults with high social standing and long life expectancy. Pups with less attentive mothers display anxiety and are more likely to suffer from heart disease and diabetes. The difference in pup behavior is correlated to an epigenetic tag. In dangerous environments, where food is scarce, mother rats have less time to be attentive. In those harsh surroundings, their anxious pups are less likely to be eaten by a predator and more likely to find food. Both of these environmentally caused epigenetic changes help pups adapt to their environment without conscious learning.
A study of men who were obese and sedentary seems to show that several months of regular vigorous exercise stimulated an epigenetic change that reduced their production of fat. Another study implies that it is a natural epigenetic process that allows certain animals to grow new limbs when one is severed. Wouldn’t that be a helpful trick to learn? Extreme stress and prolonged exposure to stress are being studied as possible epigenetic causes of PTSD and depression.
In much of the research only correlation is proven, not causation. I’ve oversimplified the subject to demonstrate opportunities to prevent and cure illnesses. They will be accompanied by troubling questions that could have come from science fiction novels. If epigenetic change can be used to produce more meat from one animal or bigger eggs or sweeter strawberries, should it be legal to do that? Who will own the intellectual property?
If we could increase our life expectancy by epigenetically delaying the aging process, should we? Should access to that epigenetic change be a “right” for everyone who wants it? If we could use our knowledge of epigenetics to pick the kind of children we want, should we? Would you choose smart? aggressive? peaceful? tall? studious? creative? What if a trait that you want also brings an increased risk of mental illness, violence, diabetes, or heart attack? If such possibilities become real who can help you use the knowledge? Will it become a medical specialty limited to physicians or will it be treated like nutritional supplements where anyone can charge a price for coaching you?
What about victims of epigenetic harm caused by pollution or harmful products? Is it just their bad luck? Do they get compensation from whoever put the chemical into the environment? Or would society as a whole share the cost?
Some epigenetic changes will be unintentional because we lack sufficient knowledge to predict the outcomes of our actions. Some decisions will be made by legislatures and others by individuals. As with nuclear energy, we will find both threats and opportunities. Today is not too soon to start acquiring the knowledge we’ll need to make intelligent choices.