Discovery of the Structure of DNA

Johann Friedrich Miescher discovers a weakly acidic substance in human nuclei he calls nuclein. It is latercalled DNA.

Jan 1, 1869

[www.dnai.org/timeline/](www.dnai.org/timeline/)

Linus Pauling discovered that many proteins take the shape of an alpha helix, spiraled like a spring coil

Jan 1, 1948

[www.pbs.org/wgbh/aso/databank/entries/do53dn.html](www.pbs.org/wgbh/aso/databank/entries/do53dn.html)

Base pairing almost unwraveled by Erwin Chargoff

Jan 1, 1949

http://www.nobelprize.org/educational/medicine/dna_double_helix/readmore.htmlErwin Chargoff shows that even though all organisms have different amounts of DNA, the amount of Adenine is always the same as the amount of Thymine

Wilkins and Gosling took the first images of DNA, producing pictures of X-ray diffraction in aligned fibres of DNA (the double helix)

Jan 1, 1950

http://www.nndb.com/people/979/000030889/

Watson and crick propose a 3 Helical model of DNA

Jan 1, 1951

http://www.nature.com/scitable/topicpage/discovery-of-dna-structure-and-function-watson-397

Rosalind Franklin Hired to improve X-ray crystallography

Jan 1, 1951

http://en.wikipedia.org/wiki/Rosalind_Franklin

Linus Pauling proposes a triple stranded Helix structure for DNA

Jan 1, 1952

[www.nobelprize.org/educational/medicine/dna...helix/readmore.html](www.nobelprize.org/educational/medicine/dna...helix/readmore.html)

Rosalind franklin uses X-ray diffraction to take photos of DNA. The patterns produced on the film by bouncing X-rays allowed the reconstruction of the 3-dimensional structure of the DNA molecule

Jan 1, 1952

http://www.sdsc.edu/ScienceWomen/franklin.html

Rosalind Franklin's 'Photograph 51' revealed the double helical structure of DNA to Watson & Crick

Jan 1, 1953

[www.nobelprize.org/educational/.../dna_double_helix/readmore.html](www.nobelprize.org/educational/.../dna_double_helix/readmore.html)Crick and Watson proposed that the structure of DNA was a winding helix in which pairs of bases (adenine paired with thymine and guanine paired with cytosine) held the two strands together

Both Wilkins and Franklin published papers on their X-ray data in the same Nature issue with Watson and Crick's paper on the structure of DNA.

Jan 1, 1953

http://www.accessexcellence.org/RC/AB/BC/Rosalind_Franklin.php

The central dogma of molecular biology was first articulated by Francis Crick

Jan 1, 1958

http://en.wikipedia.org/wiki/Francis_CrickThe central dogma of molecular biology deals with the detailed residue-by-residue transfer of sequential information. It states that such information cannot be transferred back from protein to either protein or nucleic acid.

Watson and Crick won the Nobel Prize for Physiology and Medicine

Jan 1, 1962

http://www.nobelprize.org/educational/medicine/dna_double_helix/readmore.htmlTheir Co- discoverer Rosalind Franklin did not receive any recognition in the award as it is not given posthumously