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First Discovery of DNA
Friedrich Miescher is experimenting with white blood cells, extracting certain proteins. He discovers a substance that had unusual chemical properties with high phosphorus levels. -
First Movement of DNA Studies
In the early 1900's scientists found a regular statistical pattern for features like height and colour. This discovery created an immensely popular movement in the first quarter of the 20th century and was presented as a mathematical science, which could predict the traits and characteristics of human beings. -
Mendel's theories are rediscovered
In 1900, 16 years after his death, Gregor Mendel's pea plant research finally made its way into the wider scientific community. -
Oswald Avery and the Transforming Principle
Oswald Avery an immunochemist, had worked for many years with the bacterium responsible for pneumonia, pneumococcus, and had discovered that if a live harmless form of pneumococcus was mixed with an inert lethal form, the harmless bacteria would soon become deadly.
In 1944, Avery and his colleagues published a paper, in which they outlined the nature of DNA as the 'transforming principle'. This paper would then pave the way for one of the biggest discoveries of the 20th century. -
Erwin Chargaff Finds More DNA Discoveries
In 1944, scientist Erwin Chargaff had read Oswald Avery's scientific paper, which identified DNA as the substance responsible for heredity.
Chargaff was determined to begin work on the chemistry of nucleic acids. His first move was to devise a method of analysing the nitrogenous components and sugars of DNA from different species. -
Erwin Chargaff Continued
Chargaff continued to improve his research methods and was eventually able to rapidly analyse DNA from a wide range of species. In 1950, he summarised his two major findings regarding the chemistry of nucleic acids: first, that in any double-stranded DNA, the number of guanine units is equal to the number of cytosine units and the number of adenine units is equal to the number of thymine units. -
Rosalind Franklin photographs crystallized DNA fibres
Rosalind Franklin conducted a large portion of the research which eventually led to the understanding of the structure of DNA. Franklin's role was to set up and improve an X-ray crystallography unit. She worked with a scientist and a student at King's Collage and was able to produce two sets of high-resolution photos of DNA fibres. Using the photos, she calculated the dimensions of the strands and also deduced that the phosphates were on the outside of what was probably a helical structure. -
James Watson and Francis Crick discover the double helix
Using available X-ray data and model building, they were able to solve the puzzle that had baffled scientists for decades. -
Marshall Nirenberg is the first person to sequence the bases
In 1957, Marshall Nirenberg decided to focus his research on nucleic acids and protein synthesis in the hope of cracking 'life's code'. Nirenberg created an experiment that used 20 test tubes, each filled with a different amino acid. This let the scientists know which amino acid would be incorporated into a protein after the addition of a particular type of synthetic RNA. Finally, in 1965, Nirenberg became the first person to sequence the code.