6 min|Dr. Jam Caleda

Epigenetics: Changing the Code


My mother used to say that she knows that I am her son because we both shared the maddening irritation we get from the collar tags on T-shirts. This is before I learned that maybe the sensitivity to that is related to food sensitivities or maybe the fact that collar tags are the just the worst. I certainly don’t think that genetics has anything to do with collar tags, but maybe epigenetics does.

What is Epigenetics?

Epigenetics actually means ‘above genetics’. This implies that epigenetics involves the processes that affect our genetic code. This idea arose in the 1970’s when scientists began to see that our DNA is not an absolute description of our genetics. These early researchers had observed that even identical twins, who have the exact same DNA grow to have different personalities, traits, and even diseases.

There must have been a way that the body does this, otherwise all identical twins would be mirror clones of each other. What researchers began to see is that over the course of ones life a person’s DNA does not change, however the things that we do, and in some instances what our parents and even grandparents did to their bodies affects our health.

There was an experiment performed where researchers took rats and exposed them to the sweet smell of oranges, cherries, and almond in the chemical acetophenone (1). They paired the smell of the acetophenone with a painful electric shock.

The rats quickly learned to fear this particular scent and the smell processing centers of their brains became extra sensitive to it. This result isn’t shocking, but what was interesting is that the rat pups, and the pups’ pups were also startled by the smell of acetophenone, and they actually had developed the same extra neurons that increased their sensitivity to the scent of it. This occurred despite never having been introduced to either their dads or the fruity smell of acetophenone.

So how could the baby mice have inherited something that their parents’ learned?

Basic genetics tells us that DNA codes are passed down generations, and that scars, large muscles, or memories are not, well not exactly. What we learned is that the fear that was prevalent in the first generation of rats had not changed the actual DNA that was passed on, but way the DNA is used.

How Does It Work?

Epigenetics does not look at what DNA you have, rather how DNA is expressed or used in the body and whether those expressions can be passed on to your children or even your children’s children. Each cell contains about 6.5 feet of DNA material (2), but each cell doesn’t necessarily know what to do with it. For the purposes of this next part it is pertinent to understand that DNA contains genes, which are short segments of DNA code that are 'read' and 'translated' into proteins, our building blocks of life.

There are these chemical structures called methyl-groups that determine which portions of the DNA are read and expressed. They work by binding very tightly to a gene and say, “do not express this gene!”. In different cells they bind in various ways to allow a unique expression of genes in that cell.

So even though an ear cell has the exact same code as a tongue cell they look and function very differently, thankfully. Methyl-groups can be thought of as on-off switches. Subsequently there is a structure called histones which acts as the spools which DNA wraps around.

They can change how tightly or loosely DNA wraps around them which translates to how accessible they are to the machinery of the cells expressing each gene. These histones can be thought of as knobs of control.Each cell has a distinct and unique pattern of the distribution of these methyl-groups and histones which translates to which genes are specifically expressed.

You can think of the genome, the actual DNA, as the hardware of our genetics and the epigenome, the histones and methyl-groups, as the software. The epigenome tells the genome what to do essentially.

Why is This Important?

One of the cool things about epigenomes is that, unlike our actual genomes, they can change over the course of your life. This is especially so when your body is going through major changes in your life, for example puberty, an active infection, or during childbirth. But epigenomes can also change with stress or the types of things we eat.

Scientists and researchers have actually found that the bad things we eat can change our methyl groups and allow genes that are not supposed to be expressed go into over drive, or visa versa (3). This is when things can go haywire. This is important not only for our own lives but potentially for our unborn children, or even unborn grandchildren.

We are seeing that epigenetic codes are being passed on to two generations removed from when the epigenome was created, so from our grandparents. This can be an explanation of how very healthy people can still get cancer. This is a whole new way that we think of genetics because your grandmother was making decisions that affect you today.

This idea was sparked in the 1980’s, when researchers studied a group in Norrbotten, Sweden which is in the Arctic circle (4). In the 1800’s the people relied on subsistence farming for food. It was found that boys who survived periods of famine had extremely healthy sons, with extremely low risks of heart disease and diabetes.

Their sons’ sons also had excellent health, living an average of 32 years longer than the sons of boys who hadn’t gone hungry (5). However, this does not mean that we should all start to starve ourselves for the betterment of humanity. Scientists still don’t know even exactly which switches in their epigenetic code were involved but the trend is clear that there are connections.

The more we learn about genetics the more we understand that DNA is not written in permanent ink, it’s more like in crayon. And as this field continues to provide solutions to our questions on health, it will surely generate more to be answered. But until then, I am my mother’s son, and I am my grandmother’s grandson, and I am thankful that they passed on the epigenetics that make rocky road ice cream so delicious.

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