DNA
DNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions used in the growth, development, and reproduction of all known living organisms.
DNA's double-helix structure was famously described in 1953 by James Watson and Francis Crick, drawing heavily on X-ray diffraction images produced by Rosalind Franklin and Maurice Wilkins, a discovery that revolutionized biology.
The molecule is composed of two strands wound into a double helix, made up of four chemical bases — adenine, thymine, guanine, and cytosine — whose sequence encodes genetic information passed from parents to offspring.
Understanding of DNA has since enabled advances including genetic testing, forensic science, and gene editing technologies such as CRISPR, transforming medicine and biotechnology.