On April 25, 1953, researchers wrote scientific history: they decoded the structure of our genome. However, the search did not go entirely smoothly.
When many people hear the acronym DNA, many people probably picture it: Two strands winding around each other, connected like a ladder in the middle: a double helix. But exactly this structure was a great mystery in science for a long time.
From heredity to DNA
In the middle of the 19th century, Abbot Johann Gregor Mendel experimented with pea plants in the monastery garden. He wanted to find out the rules according to which externally visible characteristics such as the color of the flowers are passed on from generation to generation. With his experiments, he laid the foundations of genetics – the science that deals with our genetic information.
But where and how this genetic information is stored was only deciphered almost 100 years later. The building blocks of DNA – short for the English deoxyribonucleic acid (German: deoxyribonucleic acid) – had been researched for decades at this point in time, but for a long time it was assumed that proteins were used to store the genetic information. It was not until 1944 that three researchers working in the USA were able to prove that DNA must be responsible for the inheritance of traits.
A scientific Puzzle
But nobody knew how inheritance worked, nor how DNA was structured. There was knowledge about their components and the ratio of these. However, it was unclear how these puzzle pieces fit together.
Several research groups worked on solving this puzzle in the 1950s. At King’s College London, biochemist Rosalind Franklin and her colleague Maurice Wilkins used X-rays to examine DNA. They discovered so many details of the DNA structure, such as which building blocks had to be on the outside and the distances between each building block.
At the same time James Watson and Francis Crick tried to develop a model of DNA with theoretical means at the University of Cambridge. To do this, they thought about possible chemical bonds and calculated the physical forces behind them. Using a model, they also considered how they could arrange the components so that everything fitted together – comparable to a chemistry kit.
data sharing behind Franklin’s back
But the riddle of the structure of DNA could not be solved by theory alone. Watson and Crick needed experimental data to point them in the right direction and support their theories.
Eventually, they also got hold of this data – albeit not entirely cleanly. Franklin’s colleague Wilkins showed the two researchers an image of the DNA that had been taken in Franklin’s lab using their X-ray technique – without asking them. In addition, the two were leaked an unofficial research report in which Franklin detailed their findings. Franklin knew nothing of this transmission either.
For Watson and Crick, these were the missing pieces of the puzzle. Franklin’s data supplemented their considerations and it became clear to them: DNA is structured like a rope ladder that winds around itself – a so-called double helix.
Nobel Prize: No appreciation for Franklin
It remains unclear to this day whether Franklin ever found out that her work was being passed on behind her back. On April 25, 1953, they published their photographs and experimental data on DNA at the same time as the Watson and Crick model in the journal Nature. Wilkins also published his data in the same issue.
Franklin died of ovarian cancer in 1958 at the age of 37. This meant that she was no longer eligible for a Nobel Prize – because it is only awarded to living people. In 1962, Watson, Crick and Wilkins received the Nobel Prize for decoding the structure of DNA. In their speeches, however, the Nobel Committee and the three laureates made no mention of Franklin’s contribution.