Who Discovered DNA?
No one person discovered DNA. Instead, many scientists uncovered more and more about DNA from 1869-1953, until it culminated in the discovery of the famous double helix.
It all started humbly enough in 1869, when Swiss chemist Johann Friedrich Miescher found a phosphorus-containing substance very different from the proteins he was looking for in white blood cells. He called this substance a nuclein, but it was later called nucleic acid.
50 years later, in 1919, Russian biochemist Phoebus Levene proposed that nucleic acids were molecules made of phosphate, sugar, and four nitrogenous bases—adenine (A), guanine (G), cytosine (C), and thymine (T).
By 1944, Oswald Avery, Colin MacLeod, and Maclyn McCarty at the Rockefeller Institute in New York showed that DNA—not proteins, as others had previously assumed—was the substance that passed along the genetic information necessary for bacterial transformation. Another important discovery came in 1950, when Erwin Chargaff published a paper outlining the rules of base pairing: adenine with thymine and cytosine with guanine.
The real breakthrough in understanding DNA, however, came with the discovery of its structure in 1953. The discovery of the structure of DNA is often credited to James Watson and Francis Crick. However they relied exclusively on the research of others, such as Rosalind Franklin, whose X-ray diffraction images of crystallized DNA were key to solving the mystery of DNA’s structure.
When Was DNA Discovered?
As previously mentioned, DNA was first identified and called "nuclein" by Swiss chemist Johann Friedrich Miescher in 1896. But its structure, the famous double helix, was not discovered until 1953 by Watson and Crick, who built upon the work of others.
Watson and Crick's quest to discover the structure of DNA began with their first meeting in the summer of 1951. The first model they proposed was wrong, featuring three strands of DNA instead of two. The turning point for Watson and Crick came when they gained access to Rosalind Franklin's work. Franklin's images and crystallographic calculations, along with the work of others such as Erwin Chargaff, helped Watson and Crick solve the mystery of DNA's structure.
Watson and Crick published their findings on the structure of DNA in a paper titled "A Structure for Deoxyribose Nucleic Acid" in 1953. Their findings fundamentally changed how scientists (and eventually everyone) thought about how the DNA molecule worked in heredity.
In 1962, Watson and Crick were awarded the Nobel Prize, together with Maurice Wilkins, for the discovery of DNA's structure. Rosalind Franklin, who had died four years before, was not included in the Nobel Prize, as a Nobel Prize can only be shared by three living scientists.
The Significance of the Discovery of DNA’s Structure
The DNA double helix is the most well-known molecular structure in all of biology. It gave a simple explanation for how DNA is copied when a cell divides, how it is passed down from generation to generation, and how such a simple molecule could provide all the mind-bending complexity displayed by life on Earth.
It is considered one of the most important scientific discoveries in modern times, leading to the development of modern molecular biology.