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Biologists on Genetics Erwin Chargaff (1905-2001)

Biologists on Genetics Erwin Chargaff (1905-2001). Relative quantities of the nitrogen bases found in DNA. Background. About Erwin Chargaff. Born in Austria on August 11, 1905 Receive a doctorate degree of Chemistry from the University of Vienna in 1928

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Biologists on Genetics Erwin Chargaff (1905-2001)

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  1. Biologists on Genetics Erwin Chargaff(1905-2001) Relative quantities of the nitrogen bases found in DNA

  2. Background

  3. About Erwin Chargaff • Born in Austria on August 11, 1905 • Receive a doctorate degree of Chemistry from the University of Vienna in 1928 • 1944 - Study of DNA and its four chemical bases - adenine, cytosine, guanine and thymine • Using chromatography technique • Discover amounts of adenine and thymine were equal, as were the amounts of cytosine and guanine

  4. The 4 nitrogen bases

  5. The 4 nitrogen bases - Purines • Consist of a six-membered and a five-membered nitrogen-containing ring, fused together • Adenine = 6-amino purine • Guanine = 2-amino-6-oxy purine

  6. The 4 nitrogen bases - Pyrimidines • Have only a six-membered nitrogen-containing ring • Uracil = 2,4-dioxy pyrimidine • Thymine = 2,4-dioxy-5-methyl pyrimidine • Cytosine = 2-oxy-4-amino pyrimidine

  7. Chargaff's first parity rule • Stated that purines pair with pyrimidines, specifically A with T and C with G • E.g ACGATGCCGTA • With pairing between complementary bases in the "top" and "bottom" strands 

  8. Chargaff's second parity rule • % of A approximately equals % of T; % of G approximately equals % of C for single strands of DNA

  9. Cluster rule • Stated that pyrimidines often occur in runs or clusters, and hence on the complementary strand purines do likewise

  10. GC rule • Stated that (G+C)% is constant within a species, but often differs between species.

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