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Miescher
Friedrich (Fritz) Miescher isolated the first crude preparation of DNA, he just did not know it. He named it nuclein. He tested patient pus-coated bandages. The term "nuclein" was later changed to "nucleic acid" and eventually to "deoxyribonucleic acid" or "DNA." More than 50 years passed before the significance of this discovery was appreciated by the scientific community. -
Chargaff
Chargaff's rules states that DNA from any cell of all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases and, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine. He used ultraviolet spectrophotometry to make these discoveries. He was opposed to cloning. -
Rosalind Franklin
She contributed to the DNA research by her taking a X-ray diffraction of DNA that showed a helical form of the molecule. Unfortunately, her photo was leaked without her permission. Watson and Crick got their proof published first. Without this photo, Watson would not have won the Nobel Prize in 1962 and we would not know the helical form of the molecule. She died of ovarian cancer at 37. Had she not died she would have received the Nobel Prize. -
Hershey and Chase
Hershey and Chase used radioactive tracers to mark the DNA core and the protein coat of the bacterial virus and placed it in a blender. This experiment showed that only the DNA had entered the bacteria. Thus, DNA is the molecule that carries genetic information for infection, growth, and development.This experiment proved that hereditary information was carried by DNA. This experiment has numerous applications in forensic science, crime investigations, and genealogy. -
Watson and Crick
By using cutouts of cardboard to represent the four nitrogenous bases (A,G,C,T) they discovered the double helix shape of DNA. They excited scientists around the world to study DNA. -
Meselson and Stahl
Meselson and Stahl discovered the basic mechanism of DNA replication as semi-conservative producing DNA molecules containing one new and old strand. Meselson and Stahl conducted their experiments in the bacterium E. coli. Today, scientists know that semi-conservative DNA replication is a universal mechanism shared by all organisms.
