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Friedrich Miescher
Miescher extracted DNA from the nuclei of a cell. He claimed it was a protein and had immense amounts of nitrogen and phosphorus. He took his DNA from human white blood cells. His original goal was to characterize proteins in human white blood cells. His discovery was not appreciated until fifty years later. -
Fredrick Griffith
Griffith was a British bacteriologist. He was trying to find a cure for pneumonia. He discovered that bacteria can change structure and function. Previously people thought bacteria was unable to be changed. Griffith used mice to demonstrate his discovery. He was one of the first to say DNA was linked to heredity. -
Barbara McClintock
After she found out that genes could be mobile she challenged the concepts of what genes were capable of. She studied chromosome breakage in maize which led her to discover a chromosome breaking locus. It was capable of changing its position within a chromosome -
Oswald Avery, Maclyn McCarty and Colin McCleod
Avery originally worked with the bacteria that causes pneumonia. At one time he wanted to discover what changes the bacteria underwent to make it deadly so he teamed up with McCarty and McCleod. The trio went on to purify 20 gallons of bacteria. They discovered it wasn't a carbohydrate or a protein. They said it was a nucleic acid. Even though they were the most qualified scientists, they did not win the Nobel prize through the 30's 40's or 50's. -
Maurice Wilkins and Rosalind Franklin
Maurice Wilkins had begun looking at proteins through an X-ray. Later Rosalind Franklin joined the task. She was an expert. In 1952 Wilkins worked with sepia sperm. In 1953 Franklin composed Photograph 51. Wilkins won a Nobel Prize not Franklin. -
James Watson and Frances Crick
Watson met Crick when he was visiting Cambridge. Despite the age difference, they became very close friends. Together they managed to solve the structure of DNA by using available X-ray data and model building. They had suspected that DNA was a helix before coming to their conclusion that DNA is a double helix. -
Erwin Chargaff
Chargaff used Avery's scientific paper, that showed DNA is responsible for heredity throughout his research. He analyzed the nitrogenous bases of DNA in different species. This research shows us the molecular build up of DNA. The DNA used was subjected to acid. He discovered that the amount of A=T and the amount of C=G. After this discovery he began speaking publicly about how molecular biology is a failure. -
Alfred Hershey and Martha Chase
The Hershey and Chase experiment confirmed that DNA is the genetic material. At this time most scientists believed that proteins carried genetic information. DNA was considered phosphorus storage. They used different element isotopes to decipher if it was DNA or a protein. They used phosphorus-32 and sulfur-35. Hershey won the Nobel prize in 1969 but Chase did not. -
Linus Pauling
Linus Pauling was very interested in nucleic acids. Pauling researched Edward Ronwin's structure of nucleic acids. He immediately knew it was incorrect. He said DNA is a helical shape that has three strands with phosphate groups in the middle. Know we know that that is molecularly impossible. Pauling won the Nobel prize at 2 different times. -
Matthew Meselsen and Franklin Stahl
Meselson and Stahl conducted an experiment known as the Meselson and Stahl experiment. They demonstrated the semi-conservative replication of DNA. They stated that each daughter DNA molecule contains one new daughter subunit and one subunit from the parent DNA molecule. They conducted this experiment at the California Institute of Technology. -
Frederick Sanger
Sanger figured out what insulin's amino acid sequence is. He was the very first person to get a protein sequence. He then made an original DNA sequencing method called the Sanger Method. -
Paul Berg
Berg started to wonder whether it would be possible to insert foreign genes into a virus so that it becomes the pathway genes could be carried into new cells. He did a gene- splicing experiment which involved splicing some of the lambda's DNA into the DNA of the simian virus whose natural host is a monkey. His experiment resulted in the first man-made recombinant DNA -
Kary Mullis
Mullis discovered the polymerase chain reaction or PCR. It is a process that allows chemists to make many copies of a specific fragment of DNA. This technique made it possible to identify the agent causing a bacterial or viral infection directly from a small sample of genetic material. -
J. Craig Venter
Venter is known for leading the first draft sequence of the human genome. He also assembled the first team to transfect s cell with a synthetic chromosome. He became frustrated with traditional methods of gene identification because they were slow and time-consuming. So he developed a different technique using expressed sequence tags or ESTs.
