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Friedrich Miescher
He was the one who extracted the substance of DNA from cell nuclei. He found out that it wasn’t a protein, but he wasn’t able to figure out its function. -
Frederick Griffith
Fredrick was studying pneumonia when he had an idea about Miechecher’s discovery. He had two strains of bacteria(harmless and lethal) that he used to see if they would cause pneumonia in mice. Heat was able to destroy the legal bacteria, so it didn’t cause pneumonia. He discovered that transformation from R cells to S cells or S cells to R cells had to do with DNA. -
Frederick Sanger
Sanger was the first to obtain a protein sequence. He figured out that genes and DNA should have a sequence just like proteins do. He won a Noble prize for Chemistry. -
Oswald Avery, Maclyn McCarty & Colin McCleod
The men were able to conclude there work that DNA is hereditary material. To prove Griffith, they used samples of lipids, proteins, and nucleic acids(RNA or DNA) from S cells. Lipids and proteins were not shown to be transporting, so they were left with DNA and RNA. RNA didn’t destroy the ability to transform, so it had to be DNA. They spent a decade trying to confirm the results. -
Barbara McClintock
She discovered that some genes can be mobile. She studied chromosome breakage and it led her to find out that a chromosome- breaking locus that could change position in a chromosome. -
Alfred Hershey & Martha Chase
They proved that it was for sure DNA that was hereditary and not proteins. They worked with bacteriophage which is a virus that infects bacteria. -
Linus Pauling
He first discovered the triple helix structure that had the bases on the outside. -
Erwin Chargaff
He discovered that any DNA molecule has the same amount of thymine and adenine. So are the amounts of cytosine and guanine and this is known as Chargaff’s rule. The second find was that there are different proportions of adenine and guanine in different species. -
James Watson & Frances Crick
They suspected that DNA was also a helix after the helical pattern of secondary structure that tends to occur in many proteins was discovered. They researched for many hours about the structure of the DNA nucleotides to find the shape, size, and bonding needs. They used cardboard cutouts and scraps of metal to try to identify the bonds. -
Rosalind Franklin & Maurice Wilkins
Franklin worked with x-ray crystallography where a x-ray goes through a purified or crystalized substance. She was able to discover the first diffraction of DNA in the cells. It showed that DNA is long compared to its diameter of 2 nanometers. -
Matthew Meselson & Franklin Stahl
They experimented to be able to prove semi- conservative replication of DNA. They used a technique called density gradient centrifugation and it is used to part molecules by their densities. They named their experiment “one of the most beautiful experiments in biology.” -
Paul Berg
He inserted DNA from bacteria into the DNA virus’. He used different organisms to make the first DNA molecule. It was known as “recombinant DNA” or “hybrid DNA.” -
J. Craig Venter
He didn’t like how slow and time consuming gene identification was, so he came up with a process that used expressed sequenced tags(EST’s). The process allowed small particles of DNA found in expressed genes, that were used as “tags.” They were used to identify genes in organisms, cells, and tissues that were unknown. -
Kary Mullis
He created the process called polymerase chain reaction(PCR). It was a process that allowed small amounts of DNA to be copied in a short amount of time as bigger quantities. When heat is added, DNA molecule strands part and the building blocks that are added attach to each individual strand.
