1 / 55

A Short History of DNA Technology

This article traces the historical development of DNA technology, from Friedrich Miescher's discovery of nucleic acid in 1869 to Watson and Crick's elucidation of the double helix in 1953.

judkinsj
Download Presentation

A Short History of DNA Technology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Short History ofDNA Technology

  2. The History Of DNA

  3. Miescher

  4. Miescher • 1869 • removed substance from pus off of old bandages • had acid properties, came from nucleus • called it “nucleic acid”

  5. Griffith

  6. 1928 - Frederick Griffith 1865 “Rough” colonies “Smooth” colonies Transformation of Streptococcus pneumoniae Living S cells Living R cells Heat killed S cells Heat killed S cells mixed with living R cells Living S cells in blood sample from dead mouse capsule Bacterial Strain Injection Results

  7. Griffith • smooth and rough bacteria • dead smooth could “transform” live rough cells • “accidental” discovery

  8. Avery, MacLeod,McCarty

  9. 1944 - Avery, MacLeod & McCarty 1865 Purified DNA as transforming factor • Work not well-received • Protein more complex & better able to store information Oswald Avery Colin MacLeod Maclyn McCarty

  10. Avery, McLeod, McCarty • separated cellular molecules • tested each for “transforming” abilities • carbohydrates, lipids, proteins were ineffective • only nucleic acids “transformed” the cells

  11. HersheyandChase

  12. 1952 - Hershey & Chase 1865 Viral DNA (not protein) programs cells Bacteriophages Martha Chase & Alfred Hershey

  13. 1952 - Hershey & Chase 1865 Radioactive protein (35S) Centrifuge and measure radioactivity in pellet and supernatant T2 Phage Bacterium Radioactivity in supernatant, but not pellet Radioactive phage infects bacterial cells Blender separates protein coats from bacterial surface

  14. 1952 - Hershey & Chase 1865 Radioactive DNA (32P) Radioactivity in pellet, but not supernatant Therefore, it is the viral DNA, and not protein, that programs cells to make copies of the virus.

  15. Hershey and Chase • chose “organism” composed only of protein and nucleic acid • infected cells with viruses tagged with radioisotopes • tagged proteins were not transferred • tagged nucleic acids were transferred

  16. Chargaff

  17. 1865 1947 - Erwin Chargoff DNA bases follow certain “rules” • Base composition is species specific • A = T, C = G for all species

  18. Chargaff • analyzed percentage of each base in DNA samples • found adenine % = thymine% • found cytosine % = guanine %

  19. Wilkinsand Franklin

  20. 1953 - Franklin & Wilkins 1865 Elucidation of the helical nature of DNA Rosalind Franklin Photographic film X-ray source Crystallized DNA Maurice Wilkins

  21. Wilkins and Franklin • X-ray crystallography on DNA to establish shape, dimensions of molecule

  22. Watsonand Crick 1953

  23. 1953 - Watson & Crick 1865 Description of the 3-D structure of DNA Francis Crick & James Watson

  24. Watson and Crick • did no original research/ relied on work of others • analyzed X-ray crystallography, biochemistry • hypothesized double-stranded helix in 1953

  25. 1953 - Watson & Crick 1865 • What they deduced from: • Franklin’s X-ray data • Double helix • Uniform width of 2 nm • Bases stacked 0.34 nm apart • Chargoff’s “rules” • Adenine pairs with thymine • Cytosine pairs with guanine

  26. 1953 - Watson & Crick 1865 • What they came up with on their own: • Bases face inward, phosphates and sugars outward • Hydrogen bonding • Hinted at semi-conservative model for replication

More Related