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Frederick Griffith
-Frederick Griffith worked with virulent S and nonvirulent R strain Pneumoccocus bacteria
-He found that R strain could become virulent when it took in DNA from heat-killed S strain
-Study suggested that DNA was probably the genetic material -
Period: to
Scientists Involved in DNA Discovery
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Erwin Chargaff
Erwin Chargaff showed the amounts of the four bases on DNA ( A,T,C,G)
In a body or somatic cell:
A = 30.3%
T = 30.3%
G = 19.5%
C = 19.9% -
Rosalind Franklin
Rosalind Franklin took diffraction x-ray photographs of DNA crystals which showed the structure of DNA as a helix. -
James Watson and Frances Crick
Watson & Crick built the first model of DNA using Franklin’s x-rays