Genetics 101

Genes are the bits of DNA that give our cells their marching orders. They make up who we are at our most basic cellular level. And the billions of cells we’re born with play an incredibly important role in our health.

When it comes to our bodies, genes run the show, telling our cells how to create the various proteins that keep us going. It’s a huge job, one that requires all our 20,000 to 25,000 genes working in harmony to give our bodies the orders that help keep us healthy.

We inherit each of our genes directly from our parents – two copies of every gene, one passed on from each of our parents. Most genes are exactly the same from person to person, but a small fraction – less than 1 percent of those thousands of genes – have slight differences. It might not sound like much, but it’s those small DNA differences that give each of us (unless you’re an identical twin) our unique set of physical features.


Scientists are still decoding all the things that happen in our cells. At their most basic level, though, genes tell our bodies how to make specific molecules called proteins that, in turn, help define our physical traits, things like eye and hair color – and also our hidden hormones and enzymes.

Proteins – large and complex and found in every one of our cells – work incredibly hard, regulating most of what goes on in our cells and playing a critical role in our tissue and organs. For starters, proteins act as antibodies, fighting off viruses and bacteria. They direct the chemical reactions in our cells. They act like messengers, transmitting signals between cells, tissues and organs. They even provide the structure and support for our cells that, on a larger scale, give us the ability to move.


A mutation is a permanent alteration in a gene that makes one of your genes different from the same gene in most other people. Some mutations affect a single tiny bit of DNA, but others span multiple genes. What’s most important to understand is that a mutation can impact your health in a lot of different ways. While, not all mutations are harmful, a gene that no longer makes a protein the body needs combined with other factors can lead to diseases like breast or ovarian cancer.

Mutations come in two variations: inherited and acquired. Inherited mutations are passed on from a parent and they’re present in virtually all your cells from day one. Inherited mutations are why it’s so important to understand your family history – inheriting a mutation linked to breast and ovarian cancer means you are at much higher risk for developing the disease in the future.

Mutations that occur because of overexposure to the sun or something going haywire during cell division are called acquired mutations. They can still lead to higher risks for disease, but they’re not a predictable part of your family tree – you can’t inherit them or pass them on.

As you take charge of your health, finding out about any inherited mutations that run in your family is one of the most proactive things you can do.

For more information about genes and how they work, visit the U.S. National Library of Medicine.


Genetics 101

Understanding Genetics is Important…

When you want to be proactive about your health
Understanding the basics of genetics—especially how mutations can lead to a higher risk of certain cancers—gives you better information about your overall health plan. About genetic testing. And about discussions to have with your healthcare provider.

When your family history indicates a pattern
A family history of cancer may mean there’s an underlying genetic cause. Once you understand how genes and mutations work, you’re better equipped to work through your family history—and better equipped for conversations with your healthcare provider or a genetic counselor.

When you’re curious or you want to fill in the gaps
A complete family history means going back at least three generations. That’s not always possible, so understanding your own genetic makeup can help you—and your healthcare provider—work backwards to fill in the gaps. And even if you’re simply curious about your own health, understanding the basics of genetics is a proactive way to get a better overall view.

“When I was diagnosed with breast cancer it was suggested that I get genetic testing. I tested positive; my sister also tested positive. She had her risk reducing surgeries and her daughters will be tested when they are 18. In the end, my breast cancer meant that my family could reduce their risk and not have to face the same thing.”