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History of DNA

 

 History of DNA

        DNA was first isolated by the Swiss physician Friedrich Miescher who, in 1869, discovered a microscopic substance in the pus of discarded surgical bandages. As it resided in the nuclei of cells, he called it "nuclein". In 1878, Albrecht Kossel isolated the non-protein component of "nuclein", nucleic acid, and later isolated its five primary nucleobases.

        In 1909, Phoebus Levene identified the base, sugar, and phosphate nucleotide unit of the RNA (then named "yeast nucleic acid").  In 1929, Levene identified deoxyribose sugar in "thymus nucleic acid" (DNA). Levene suggested that DNA consisted of a string of four nucleotide units linked together through the phosphate groups ("tetranucleotide hypothesis"). Levene thought the chain was short and the bases repeated in a fixed order. 



        In 1927, Nikolai Koltsov proposed that inherited traits would be inherited via a "giant hereditary molecule" made up of "two mirror strands that would replicate in a semi-conservative fashion using each strand as a template". In 1928, Frederick Griffith in his experiment discovered that traits of the "smooth" form of Pneumococcus could be transferred to the "rough" form of the same bacteria by mixing killed "smooth" bacteria with the live "rough" form. This system provided the first clear suggestion that DNA carries genetic information.

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

    In the above article processed the following information:

  1. The First Piece of the Puzzle: Miescher Discovers DNA
  2. Laying the Groundwork: Levene Investigates the Structure of DNA
  3. Strengthening the Foundation: Chargaff Formulates His "Rules"
  4. Putting the Evidence Together: Watson and Crick Propose the Double Helix



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