The Road to the Double Helix, the Structure of DNA

Fifty years ago, on April 25, 1953, James Watson and Francis Crick published a short letter in the science magazine Nature . It described a remarkable two-chain helical structure for DNA--the genetic material in living organisms. Their double-helix model provided the key to understanding how living cells can produce two exact copies of themselves and how genetic material stores all the information for synthesizing the proteins needed to build a living organism.

A second major advance came a few months later, when Max Perutz discovered a technique to determine the structures of large molecules like myoglobin and hemoglobin. Since then, X-ray structural analysis of protein molecules has helped us to understand the chemistry of biological reactions.

Both discoveries--DNA structure and protein structure--were made at Cambridge University's Cavendish Laboratory. So why were these two foundation stones of the revolution in biology and medicine that dominated science in the second half of the 20th century uncovered in a British physics lab?

The great breakthroughs of 1953 rested on the strength of experimental physics at Cambridge, beginning in the late 19th century. This legacy shaped the intellectual environment in which the father-and-son team of William and Lawrence Bragg were trained, and where Lawrence Bragg--first as an undergraduate and then as a research student--developed in 1912 the ideas that led to X-ray structural analysis.