The structure of DNA
Life's recipe turns out to be a double helix
See it on the timeline →In depth
The model depended critically on Rosalind Franklin's X-ray diffraction Photograph 51, for which she received no credit in her lifetime. Complementary base pairing explained both replication and mutation in a single structure — rarely has form been so revealing of function. From this flow genetic engineering, PCR, DNA sequencing, forensics, modern evolutionary biology and personalised medicine. The human genome was completed in 2003, almost fifty years to the day later.
For children
Watson and Crick worked out what our genetic material looks like: two strands twisted around each other like a spiral staircase. The shape immediately explains how cells can copy the recipe for you every time they divide.
Connects to
Part of Terra Saga — the story of Earth on a timeline. terrasaga.org