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Johannes Miescher
Miescher extracted DNA from cell nuclei and determined that it was not a protein. He discovered that it was rich in nitrogen and phosphorus. However, it’s interesting that he did all this work but nothing new was uncovered for another 60 years. The extracted DNA was placed in a tube to be examined, as seen in the picture. -
Frederick Griffith
The interesting thing about Griffith’s discoveries is that they were found while he was trying to create a vaccine. He was doing an experiment on mice when he found that heat destroyed the lethal strains of bacteria but did not destroy the heredity information. -
Oswald Avery, Maclyn McCarty & Colin McCleod
They had assumed that DNA was made of proteins and they were shocked when they found out that DNA and RNA were nucleic acids. They used process of elimination to figure out the identity of DNA. As seen in the picture they tested different strands to find the correct structure. -
Barbara McClintock
She did work on plants specifically. She discovered that DNA could rearrange itself and reorganize. This was called jumping genes and it describes corn cobs. The kernels were rearranged embryo’s. -
Alfred Hershey & Martha Chase
These two scientists also were working on viruses and bacteria when they found their discovery. They found that DNA satisfies the first property of a hereditary molecule. DNA transmits a full complement of hereditary information. The picture helps explain the process they used to find the information. -
Erwin Chargaff
He made two very important discoveries. The discoveries concluded that the amounts of thymine and adenine were identical and the same went for cytosine and guanine. He also noticed that the amount of thymine and adenine differed between species. I find it interesting that he was able to figure out that the amounts can differ between species, because the discovery was still new. -
Linus Pauling
Pauling figured out the structure of proteins. It was a spiraling structure. This information was used to figure out that DNA was not made of proteins. This discovery made him known as the founder of molecular biology. The picture shows some of his notes and a 2d drawing of the structure. -
Rosalind Franklin & Maurice Wilkins
Rosalind Franklin used x-ray crystallography to create a series of photos in hope of finding the structure of DNA. The photo that showed the structure was known as photo 51. Franklin was passionate about her work but because of being exposed to x rays so often she had to take many breaks. That gave time for Wilkens to provide her work to Watson and Crick and that led them to their discovery of the structure. The picture shown is photo 51. -
James Watson & Frances Crick
Watson and Crick used information from Rosalind Franklin to come up with the structure of DNA. They found that it was a double helix structure that held human genes. They proved their work by using models. What’s interesting is that Franklin’s work was never given credit and that’s what led Watson and Crick to tier discoveries. Many years later and she is finally getting some credit for photo 51. The picture shows what the model looked like. -
Frederick Sanger
Sanger figured out that because proteins have a sequence, so should amino acids. Which made it true that DNA had a specific sequence as well. Each sequence was unique. He earned a Nobel prize from this work because it led to learning more about insulin. The picture shows a specific sequence. -
Matthew Meselson & Franklin Stahl
Their research on DNA replication confirmed that Watson and Crick’s work was true. The DNA was wound together in a double helix structure and when they separated it created two daughter cells. A debate drove Meselson and Stahl to find these answers and confirm the structure of DNA. This model shows the process of DNA replication. -
Kary Mullis
Mullis made his discovery using TaqMan. What he found was that small amounts of DNA could be copied in very short time spans. When heat is applied the DNA strands separate and DNA building blocks are bonded to each strand. This process was known as polymerase chain reaction. He used Sanger’s knowledge of protein sequencing to create this idea. -
Paul Berg
Berg was studying tumor viruses and decided to insert DNA from bacteria into the virus’ DNA. He created the first DNA molecule that was made using parts from other organisms. It was known as “hybrid DNA”. I find it interesting that most discoveries were made by starting with the study of a virus. Berg follows that pattern with his discovery. -
J. Craig Venter
Venter first drafted a sequence of a human genome. He also assembled scientists to help him transfect a cell with a synthetic chromosome. He used information from past scientists to make newer discoveries. His discoveries were more advanced due to new technology. This picture shows what advanced technology can show us from genes.
