DNA
DNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions used in the growth, development, and reproduction of all known living organisms.
The double-helix model that made two scientists famous relied heavily on an X-ray image produced by a colleague who received almost no credit for it during her own lifetime.
Discovering the Double Helix
DNA's iconic double-helix structure was famously described in 1953 by scientists James Watson and Francis Crick, a discovery that revolutionized biology and is considered one of the most important scientific breakthroughs of the 20th century.
A Discovery Built on Overlooked Work
Watson and Crick's model relied heavily on X-ray diffraction images produced by scientist Rosalind Franklin and her colleague Maurice Wilkins, showing the molecule's helical structure — critical evidence that was shared with Watson and Crick without Franklin's knowledge, a contribution only widely recognized decades later.
The Structure of Life's Code
DNA consists of two intertwined strands forming a double helix, built from four chemical building blocks called bases — adenine, thymine, guanine, and cytosine — whose specific sequence encodes the genetic instructions passed from parents to offspring across every form of life.
Transforming Human History
Understanding DNA's structure and function is believed to have evolved through natural processes stretching back nearly 4 billion years, and modern genetic science built on Watson and Crick's discovery has enabled advances including genetic testing, forensic identification, and paternity testing.
Editing the Code of Life
More recently, gene-editing technologies such as CRISPR, developed in the 2010s, have given scientists the unprecedented ability to precisely edit DNA sequences, opening new frontiers in medicine, agriculture, and biotechnology while raising significant ethical questions about the limits of genetic modification.
