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Meischer
Meischer used white blood cells from pus on bandages to make this discovery. He isolated the new molecule "nuclein" from the cell nucleus. He said that nuclein was made up of hydrogen, oxygen, nitrogen, and phosphorus. Meischer then used salmon sperm instead of pus to experiment with. He also studied the metabolic changes in salmon when they spawn. -
Chargaff
Erwin Chargaff worked closely with many of his colleagues to do what he needed to make this discovery. He was inspired by Avery's experiment which suggested that living things differed because of differences in their DNA. He then used partition chromatography to separate DNA into it's components for analysis by ultraviolet spectrophotometry. He discovered that different species have different amounts of bases and fixed ratio of bases. He also came up with Chargaff's rule. -
Rosalind Franklin
Franklin was directed to a man named Marcel Mathieu who offered to help her. Once she was done learning everything he could teach her, she then went on to learn x-ray diffraction techniques from Jaques Mering. with her knowledge of x-ray diffraction she began to improve an x-ray crystallography at kings college. After working with a student, she captured two sets of high resolution pictures of crystallized DNA fibers. She presented this at a lecture which Watson and Crick attended. -
Hershey and chase
Alfred Hershey and Martha Chase used man different experiments to prove that DNA was the genetic material. They grew viruses in isotopic mediums and allowed to infect E coli. The virus and bacteria were then separated with centrifugation. This experiment proved that DNA in fact, was the genetic material. -
Watson and Crick
The two scientists used other scientists information about the DNA molecule. They both suggested that there were two sides to the DNA molecule. These two sides were composed of nucleotide chains . This discovery later became known as the double helix. Watson and Crick also said that each DNA strand was a template for another. When cell division occurred, an old strand is combined with a new one so that the DNA could replicate without changing is entire structure, -
Meselson and Stahl
They cultured bacteria in a test tube and then shifted it to another, The DNA was isolated at different times corresponding to replication cycles. After two replication cycles, two DNA bands were seen. This became the discovery of semi-conservative DNA replication.
