What Is DNA?
By Brandon Colby, MD, Physician specializing in genetic analysis and personalized preventive medicine, and author of Outsmart Your Genes.
DNA (deoxyribonucleic acid) is the molecule that carries the instructions an organism needs to develop, function, and reproduce. It is made up of four chemical bases — adenine (A), thymine (T), guanine (G), and cytosine (C) — arranged in a specific order along two intertwined strands that form a double helix. The sequence of these bases functions like a code, determining everything from eye color to how the body processes medications.
DNA is packaged into structures called chromosomes, which are found in the nucleus of nearly every cell in the body. Humans inherit half of their DNA from each biological parent, which is why DNA is central to genetic inheritance, ancestry, and the study of hereditary disease risk.
References: medlineplus.gov/genetics; nih.gov (National Human Genome Research Institute)