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Friedrich Miescher
A chemist who first identified DNA as a distinct molecule when he isolated "nuclein" (aka DNA with associated proteins) from pus cells. He also discovered that "nuclein" contained a substance termed nucleic acid and that DNA is not a protein, but it is rich in nitrogen and phosphorus. -
Frederick Griffith
Unexpectedly uncovered a clue about DNA's function in 1928. While studying pneumonia-causing bacteria, Griffith isolated two strands of bacteria--one harmless (R) and the other lethal (S). Through a series of experiments performed on mice, he discovered that the R bacteria can be turned into the S bacteria through the process known as transformation. -
Barbara McClintock
Barbara McClintock found that genes could move from chromosome to chromosome. These studies led to her discovering chromosome breaking and how it changed it's position. She often faced sexual discrimination and people didn't recognize her for her contributions. McClintock was the 1st women to win the Noble Prize without sharing it. -
Oswald Avery, Maclyn McCarty, & Colin McCleod
Carried out experiments that they hoped would help to find the substance that carried out transformation. They did this by extracting S cells and realized said cells could still transform R cells after being treated with lipid and protein destroying enzymes. This then helped them realize that the "transforming principle" they were looking for was a nucleic acid. Eventually, they were able to rule out RNA, making DNA the "transforming principle." They also discovered DNA was hereditary material. -
Erwin Chargaff
Discovered two things about DNA. The first one being that the amounts of thymine and adenine are identical and so are the amounts of cytosine and guanine. The second one being that DNA of different species differs in its proportions of Adenine and Guanine. These discoveries became known as "Chargraff's Rules" and helped to create a new approach to the study of the biology of heredity. -
Linus Pauling
Discovered the spiral structure of proteins which helped to make it possible for geneticists to crack the DNA code of all organisms. This also then made it possible to develop techniques that would prevent inheritance of genetic disorders. Although Pauling incorrectly proposed the idea of a triple helix structure with the bases on the outside, his idea helped in Watson and Cricks discovery of the double helix structure of DNA. -
Alfred Hershey & Martha Chase
Were able to prove that--instead of protein--DNA was the hereditary material in viruses after experimenting with bacteriophage--a type of virus that infects bacteria. Their experiments were based on the knowledge that proteins contain more sulfur than phosphorus and DNA contains more phosphorus than sulfur. -
Rosalind Franklin and Maurice Wilkins
Rosalind Franklin and Maurice Wilkins made the first clear X-ray diffraction image of DNA as it occurs in cells. Their discoveries helped Watson and Crick finish their double helix model. Rosalind Franklin took the famous "Photo 51" in 1951. Rosalind died of cancer at age 37, but Wilkins did go on and receive the noble prize in 1962. -
James Watson and Frances Crick
James Watson and Frances Crick found the structure of DNA. They were the 1st scientists to determine the correct structure of the DNA double helix. They used "photo 51" to create the structure which was taken by Rosalind Franklin. They were able to conclude that DNA is a double helix polymer, and within each strand, there are long strands of nucleotides. He announced the discovery in pub yelling "We found the secret of life". -
Matthew Meselson and Franklin Stahl
Discovered that DNA replication was semiconservative. They were able to show how--when split into two--each new DNA molecule would be made up of half of the old DNA and half of the new DNA. The experiment that Meselson and Franklin conducted to make this discovery was very complex and known as "the most beautiful experiment in biology." -
Paul Berg
Paul Berg spliced a gene from 1 bacterial virus into the DNA of a completely different virus. This was the first rDNA. I found it interesting that they stopped experiments with this bacteria for a little because of the concern if rDNA escaped the labs. Awarded the Noble Prize in 1980 with Frederick Sanger and Walter GIlbert. -
Frederick Sanger
Sanger created the rapid DNA sequencing technique to find the order of bases in strands of DNA. Enzymes are added to synthesize pieces of DNA and they end when a base is inserted to the DNA being synthesized. This then allowed him to use a radioactive marker to identify the individual bases. An interesting fact about Frederick Sanger is that he is 1 of 3 people to ever win the Noble Prize twice. -
Kary Mullis
Mullis invented the Polymerase Chain Reaction, which multiples a single DNA strand billions of times in hours. PCR basically provides an unlimited supply of DNA for scientists to experiment or analyze on. PCR enables scientists to take DNA out of fossils allowing the creation of an entirely new field, paleobiology. -
J. Craig Venter
Craig Venter believed the shotgun sequencing was the best for the human genome data. While others didn't approve because it was too fast or it couldn't give enough details. The people doubted him, but he announced the sequencing of the whole human genome. The discovery he and other people made can result in treatments for diseases, from diabetes to heart disease to Alzheimer. .
