DNA discoveries

Timeline created by alessandrol46
  • Charles Darwin published Origin of Species

  • Gregor Mendel's "inheritance factors in peas" results

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    Linus Pauling

    Discovered alpha helix
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    Barbara McClintock

    In 1920s studied how chromosomes change during reproduction of corn. She used microscocopic analysis to demonstrate many fundamental genetic ideas including genetic recombination as a result of crossover.
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    Alfred Hershey

    Received PhD at Michigan State University
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    Maurice Wilkins

    Studied physics at St. John's College, Cambridge and was a physicist and molecular biologist. With Franklin, experiment showed that DNA had helix shape and DNA had a diameter of 2nm and it completed a turn in its helix every 2.4nm
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    Rosalind Franklin

    Went to Newham College, Cambridge and studied chemistry. Franklin and Wilkins used X-Ray diffraction to analyze DNA where a beam of X-Rays bombards a molecule. The X-Rays are diffracted when they hit the moleculs and then are recorded on photographic film.
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    Martha Chase

    PhD at USC and College of Wooster. With Hershey, found that DNA, not the protein, caused transmission of genetic information. Found genes are made of nucleic acid DNA
  • Fred Griffith proposed some unknown 'principle' transforms harmless R strain of Diplococcus to virulent S strain

    Griffith's experiment, conducted in 1928 by Frederick Griffith, was one of the first experiments suggesting that bacteria are capable of transferring genetic information through a process known as transformation. His experiment suggested that protein was not the genetic material. Injected mice with deadly bacteria and all mice died. After he killed the virulent bacteria cells by heating them and the mice injected with them did not die. However, only some mice died when he mixed both.
  • Avery backs up Griffith

    Purified transforming 'principle' in Griffith's experiment and that it was DNA
  • Crick worked out theory of X-Ray diffraction by a helix

  • Erwin Chargaff discovered 1-1 ratio of adenine to thymine and guanine to cytosine in DNA

    Added chemicals to break DNA apart and noticed pattern of the 4 bases. Collected DNA from many different samples.
  • Rosalind Franklin obtained X-Ray diffraction photographs of DNA

  • Chase and Hershey used phages in which protein was labeled 35S and DNA with 32P for the final proof that DNA is the molecule of heredity.

  • Watson and Crick solve 3D structure of DNA molecule

    Used ‘stick-and-ball’ method to model various possible DNA structures.
  • Pauling received Nobel Prize in chemistry

  • Hershey won the Nobel Prize in Physiology or Medicine

    Won for the discovering properties of DNA
  • Pauling received Nobel Peace Prize

  • McClintock won nobel prize

    Won for her work on "jumping genes" and elected member of National Academy of Sciences.
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    Human Genone Project

    Goal of coding entire DNA sequence in human chromosomes. (Collins and Ventner)
  • Francis Collins discovery

    Identified gene coding for cystic fibrosis transmembrane conductance regulator protein (CFTR) on chromosome 7 that causes cystic fibrosis when mutant.