Hurray for DNA!
By Karen McKenany-Phillips

Before you were even born, a secret code helped build the perfect you. It’s the reason behind the color of your eyes and hair. Even the birth mark on the back of your knee was carried out by this unique code. And it’s tucked inside every one of the 100 trillion cells in your body!

The code's name is DNA. That stands for de-ox-y-ri-bo-nu-cle-ic acid. Every living thing is made up of deoxyribonucleic acid with special orders to make that living thing look like it's supposed to. That's why frogs have strong legs to jump, monkeys have long arms to swing, and oak trees grow thick trunks with many branches.

More than half a century ago, in 1953, two scientists, Dr James Watson and Dr. Francis Crick, discovered how DNA works. These men were curious about the secrets of life. But other scientists were trying to find out how DNA worked too. Soon there was a race to see who would crack the code first. Dr. Crick and Dr. Watson worked super hard and even made mistakes along the way. But they didn't give up until they found the answers.

Small but mighty

What does DNA look like? Here’s what Dr. Crick and Dr. Watson found out. Imagine a long, twisting licorice ladder with lots of steps. The ladder is called a helix. But remember that DNA is tiny when it is curled up inside a single cell. Smaller than the tip of an ant's baby toenail! Yet if you stretched this twisting ladder from end to end, it would be as tall as your bedroom wall.

What is the secret code? DNA uses the letters A, C, G, and T to make up the secret code. These letters were designated by scientists, and are paired in a certain way. If something goes wrong with this code, it can make you sick. That’s why learning about DNA helps doctors fight diseases, like muscular dystrophy (MD) and cystic fibrosis.

How does DNA get in all of your cells? As you grow, the cells that build your body divide in two, over and over again. The DNA ladder in each cell, "unzips"--like the zipper on your jacket, so the secret code is cut in half. Each half of the ladder rebuilds itself and soon a complete DNA helix or ladder forms in the two new cells.

Special Spit

Scientists can discover your DNA from a piece of hair stuck in your hairbrush or the saliva on the straw in your juice box. These samples from your head and mouth can be used to unlock your secret code. And your DNA actually looks a lot like your family members. This explains why you and your brother share so many similar features, from nose shape to shoe size. But DNA doesn’t affect personality like it does appearance.

Just like your fingerprints help identify you, so does your DNA. Still, DNA doesn’t have all the answers. If you always have your nose in a book, while your brother prefers to wrestle with his buddies, you have more than DNA to thank for your differences!