National DNA Day

By 1952, scientists knew DNA carried genetic information but had no idea what it looked like. Two teams raced to solve the structure: James Watson and Francis Crick in Cambridge, and Maurice Wilkins and Rosalind Franklin at King's College London. Franklin was the world's leading X-ray crystallographer of the period. In May 1952, she captured Photo 51 the clearest X-ray diffraction image of DNA ever taken. It showed a helix.

In January 1953, Wilkins showed Photo 51 to Watson, without Franklin's permission or knowledge. Watson and Crick spent the next weeks building wire-and-cardboard models, and on April 25, 1953, they published the now-famous 1,000-word paper in Nature announcing the double-helix structure. In 1962, Watson, Crick, and Wilkins won the Nobel Prize for the discovery. Franklin had died of ovarian cancer four years earlier, at age 37, and was not credited.

The 50-year project to read the entire human genome, the Human Genome Project, was declared complete on April 14, 2003, 50 years (almost to the day) after Watson and Crick's paper. Cost: $2.7 billion. Today, you can sequence your own genome for under $300. The speed of that cost collapse is the fastest in the history of technology faster than Moore's Law, faster than any biotech revolution before or since.

National DNA Day was declared by Congress in 2003 to mark both anniversaries. It's a rare American holiday that celebrates a scientific moment, and a rarer one that asks us to reckon with who gets credit. Rosalind Franklin's photograph made the discovery possible. Her name belongs on every DNA Day.

The four ways DNA quietly shapes your life:

Six moments that changed what DNA means: