Most people have 23 pairs of chromosomes, for a total of 46 pairs. Portions of it are tightly bound into packages known as chromosomes. Where is DNA in the body?ĭNA exists inside the nucleus of each of the body’s cells. The remaining one percent is responsible for the countless features-like eye color, skin tone, and body shape-that make each person unique. Those bases form the blueprint that gives rise to the shared traits that are characteristic of our species. Human DNA has roughly three billion bases, and 99 percent of them are the exact same in every person.

The order, or sequence, of these base pairs is critically important because it determines the genetic code that gives rise to specific life-forms, from humans to hamsters to hibiscus. Picture a ladder that twists like a corkscrew, with the sugar and phosphate acting as the side rails and the base pairs acting as the rungs. In 1953, scientists proposed that DNA is structured as a double helix, with the chemical bases-adenine (A), cytosine (C), guanine (G), and thymine (T)-stacked up in pairs between two intertwining lengths of sugar and phosphate. Thousands of times thinner than one of the hairs on your head, a strand of DNA consists of three chemical building blocks: a sugar group, a phosphate group, and one of four nitrogen-containing bases. It helps cells make proteins, which they need to survive, and it facilitates reproduction. Chemistry with a twistĭNA, or deoxyribonucleic acid, is a molecule found inside every cell in almost every living thing. Without setting foot in a fancy science lab, this is how you can see the intricacies of a person’s DNA. Next time you’re holding hands, pay attention to the shape of her fingers. Notice the curve of her smile and the special way her forehead creases when she laughs.

DNA.com by Morton Chalfy