Epigenetics: Annotations in the Book of DNA

Phrases like “that runs in the family” and “You got that from your grandma” are thrown around all the time. We can see in our family resemblances that we inherit traits, both physical and behavioral, from our parents. This is because of heredity and genetics: these traits are coded for by DNA, a molecule that is passed from parents to children. Recently, though, scientists have begun to realize that our DNA is only the beginning of the story.

We can think of DNA as a book. Every cell in the body has the same book inside of it. How the book is understood by the cell, however, can change by being annotated. How are these annotations made? Epigenetics. Epigenetics, meaning “above genetics,” is the study of how one’s surroundings can affect the expression of DNA- or the annotations in the book. Different environmental factors can change or add annotations, fundamentally affecting how the genes we inherited from our parents are expressed in us.

For example, baby rats who are nurtured by their mothers grow up to be calm, and rats who are neglected grow up to be anxious. This is more than just a behavioral response. The rat’s DNA books are altered, and gene regulation actually changes in response to the environment they were in. The most fascinating part is that many of these annotations aren’t wiped clean when the book is passed on to the next generation. They stay, and can affect the epigenetics and gene expression of the offspring. So, our DNA books are scribbled on all over. Some of the annotations come from what we have experienced, some come from our parents, from our grandparents, or many generations back.

Our understanding of epigenetics is still developing, but this is an incredible discovery. It will be exciting to see all of the environmental factors we are exposed to can change our DNA, and the way our genes are expressed.

Rat example: https://learn.genetics.utah.edu/content/epigenetics/rats

This was written as an assignment in WRIT 105ST at UCSB.