DNA History & Structure


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DNA History & Structure

  1. 1. DNA
  2. 2. DNA <ul><li>Deoxyribonucleic Acid </li></ul><ul><li>Very large molecule that carries genetic information of an organism </li></ul>
  3. 3. DNA History
  4. 4. 1865 <ul><li>Gregor Mendel generalized a set of rules governing inheritance, using a pea plant. </li></ul><ul><li>Described “units of heredity,” which are called genes. </li></ul>
  5. 5. 1869 <ul><li>Meischer isolated DNA for the 1 st time </li></ul>
  6. 6. 1928 <ul><li>Fred Griffith discovered transformation. </li></ul><ul><li>Worked as a health service worker. </li></ul><ul><li>Injected virulent bacteria into mice, resulting in death. </li></ul>
  7. 7. 1944 <ul><li>Avery, MacLeod, and McCarty isolated the “factor” as the compound DNA. </li></ul><ul><li>DNA is defined as the genetic material!! </li></ul>
  8. 8. 1948 <ul><li>Erwin Chargaff discovered DNA of all species are mainly the same. </li></ul><ul><li>The main difference is the proteins made by each individual. </li></ul>
  9. 9. 1950 <ul><li>McKlintock published proof of transposons, “jumping genes,” by using corn. </li></ul><ul><li>She won the Nobel Prize in 1983 for her work. </li></ul>
  10. 10. 1952 <ul><li>Rosalind Franklin took x-ray pictures of DNA crystals. </li></ul><ul><li>She was able to determine the relative shape and size of DNA. </li></ul>
  11. 11. 1953 <ul><li>James Watson and Francis Crick, working together at Cambridge, discovered the structure of DNA. </li></ul><ul><li>They did this based on the x-rays and studies of Franklin. </li></ul>
  12. 12. 1958 <ul><li>Meselson and Stahl used a density centrifugation to demonstrate semi-conservative replication of DNA. </li></ul>
  13. 13. 1990 <ul><li>The Human Genome Project </li></ul><ul><ul><li>A 15-year project designed to map EVERY gene in the human body!! </li></ul></ul>
  14. 14. 1997 <ul><li>Dolly, the lamb, was the 1 st mammal to be cloned from an adult using modern techniques of cloning. </li></ul><ul><li>She was cloned at the Roslin Institute in Edinburgh. </li></ul>
  15. 15. 1999 <ul><li>1 st chromosome is sequenced </li></ul>
  16. 16. 2000 <ul><li>Human genome “draft” is completed. </li></ul><ul><li>Leaders announced the completion of a “working draft” DNA sequence of the human genome. </li></ul><ul><li>The post-genomic era begins!! </li></ul>
  17. 17. Structure of DNA DNA and RNA: Polymers of Nucleotides
  18. 18. DNA and RNA <ul><li>Both are nucleic acids. </li></ul><ul><li>Consist of polymers of nucleotides, which are made up of: </li></ul><ul><ul><li>A nitrogenous base </li></ul></ul><ul><ul><li>Sugar (Ribose or Deoxyribose) </li></ul></ul><ul><ul><li>Phosphate group </li></ul></ul><ul><ul><li>A repeating pattern, called a sugar-phosphate backbone </li></ul></ul>
  19. 19. DNA and RNA (con’t) <ul><li>Nitrogenous bases are arranged like appendages along the backbone. </li></ul><ul><li>Nucleotides differ only in the nitrogenous bases: </li></ul><ul><ul><li>Thymine (T) and Cytosine (C) are single-ringed structures </li></ul></ul><ul><ul><li>Adenine (A) and Guanine (G) are double-ringed structures </li></ul></ul><ul><ul><li>RNA uses Uracil (U) in the place of Thymine </li></ul></ul>
  20. 20. The Double Helix <ul><li>Scientists working on the DNA structure were: </li></ul><ul><ul><li>Linus Pauling </li></ul></ul><ul><ul><li>Maurice Wilkins </li></ul></ul><ul><ul><li>Rosalind Franklin </li></ul></ul><ul><ul><li>James Watson </li></ul></ul><ul><ul><li>Francis Crick </li></ul></ul>
  21. 21. Helix (con’t) <ul><li>Using x-rays, Watson and Crick were able to determine the diameter of the helix was uniform and that it was a double helix. </li></ul><ul><li>After trying to replicate the structure, they found: </li></ul><ul><ul><li>A sugar-phosphate backbone on the outside, forces the nitrogenous bases to the interior. </li></ul></ul><ul><ul><li>The 4 bases pair specifically. </li></ul></ul><ul><ul><li>The chemical side groups are bound with hydrogen bonds. </li></ul></ul><ul><ul><li>A binds to T and G binds to C, keeping the helix uniform. </li></ul></ul>