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Miescher
Friedrich Miescher discovered DNA by making arrangements for a clinic to send him patient pus-coated bandages. He planned to wash them and filter out various proteins within the white blood cells. He identified what he called "nuclein" inside the nuclei of human white blood cells. -
Miescher Continued
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. Without this groundbreaking discovery, Watson and Crick may never have reached their conclusions that the DNA molecule exists in the form of a three-dimensional double helix. -
Chargaff
He gave us the Chargaff Rule that states that the number of adenine always equals the number of thymine. Also the number of guanin always equals the number of cytosine and the the number of purines equals the number of pyrimidines. -
Chargaff Cont.
An that these are the basic facts you need to now if you want to construct and accurate model of the DNA double helix. He discovered that different species have different amounts of bases. He came about this discovery by using ultraviolet spectrophotometry. He opposed cloning and gene manipulation. -
Franklin
Rosalind Franklin contributes to the DNA by her taking a X-ray diffraction of DNA that showed a helical form of the molecule. Unfortunately, her photo was leaked and she didn't get credit for finding the double helix first because Watson and Crick got their proof published first. Her photo was leaked without her permission to Watson. Without this photo, Watson would not have won the Nobel Prize in 1962 and we would not know the helical form of the molecule. -
Hershey & Chase
Hershey hired Chase to prove whether DNA is the molecule that carries genetic information or its associated protein carried the genetic information for infection, growth, and development. They 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. -
Hersey & Chase Cont.
The Hershey-Chase experiment served to establish that hereditary information was carried by DNA. This finding has numerous applications in forensic science, crime investigations, and genealogy. -
Watson and Crick
They discovered the double helix by using cutouts of cardboard to represent the individual chemical components of the four nitrogenous bases(A,G,C,T) by messing around with the cutouts they were able to put the pieces together like a puzzle. -
Watson and Crick Cont.
They were not the discoverers of DNA. They were the first scientists to accurately describe this molecule's complex double-helical structure. Thanks to their research scientists are still making great strides in understanding the human genome and the importance of DNA to life and health. -
Meselson & Stahl
They established the basic mechanism of DNA replication as semi-conservative producing DNA molecules containing one new and old strand. They did their experiments in the bacterium E. coli. we know today that semi-conservative DNA replication is a universal mechanism shared by all organisms on Earth.
