Frequently Asked Questions (FAQs)

1. What is DNA?

DNA is a long sequence of letters (about 3 billion letters, in fact!) that acts as our body’s own set of instructions. Bodies read our DNA to know how to build and maintain all of our cells, tissues, and body organs. Although most of our DNA sequence is the same from person to person, our DNA sequence is unique to us; it is our genetic “signature” or “fingerprint.”

2. What is a mutation?

While about 99.9% of our DNA sequence is identical in all human beings, the variation in our DNA is what gives us our unique characteristics. For example, differences in our DNA code for our eye, skin, and hair colors, influence how tall we will be, and can even play a part in our personality and behavior. Although much of the variation in our DNA is harmless, changes in very specific letters in our DNA sequence can result in health problems. These disease-causing “spelling errors” in our DNA are called “mutations.”

3. What is a gene?

Because our DNA is very long, in order to read through it quickly and effectively, our DNA is organized into tiny sections called “genes.” It is helpful to think of DNA as the body’s instruction manual and its genes as its chapters. For example, if you were putting together a chair, you would look for specific chapters in the instruction manual on how to assemble each individual part of the chair. In the same way, the body refers to specific genes to figure out how to grow and develop its different components properly.

4. How do mutations cause disease?

Mutations in specific genes cause the body to misread the gene. Going back to our example of the instruction manual for a chair, imagine you are trying to put together the legs of the chair. You find the chapter on “Assembling Chair Legs,” but, unbeknownst to you, there is a typo; instead of “Insert leg into Slot A,” the instruction manual tells you to “Insert leg into Slot B.” Following the instructions, you screw the leg into Slot B and see that the chair leg is now completely in the wrong place. These typos, or mutations, in the gene "chapters" confuses the reader and causes him/her to assemble the chair incorrectly. Similarly, the body reads through the mutations in a gene and build itself in an unexpected, unintended way.

5. What is a genome?

The genome is our complete set of our genetic instructions. It comprises our entire DNA sequence. Our genome can be found in each one of the trillions of cells that make up our bodies.

6. What is genome sequencing?