The Genetic Timeline

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The Genetic Timeline
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Friedrick Miescher From Pus soaked rags Miescher
was able to isolate the nuclei from white blood
cells. In the nuclei he finds a chemical he
calls Nuclein Function is unknown of this
mystery chemical, but it contains a lot of
phosphate
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• Phoebus Levine
• Over time Meischers nuclein was found to be a
  major part of chromosomes
• Through hydrolysis Nuclein contained
• Unique sugar called deoxyribose
• Phosphate
• 4 kinds of nitrogen bases

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Nitrogen-containing bases
Nuclein
Deoxyribose (sugar)
Phosphate
Hydrolysis
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Levine figured that each nitrogen base was attach
to a sugar
Each sugar was then attached to a phosphate group
This arrangement of molecules was called a
nucleotide and is specifically named for the
nitrogen base it contains
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• Phoebus Levine
• Meischers nuclein a major part of chromosomes
• Through hydrolysis Nuclein contained
• Unique sugar called deoxyribose
• Phosphate
• 4 kinds of nitrogen bases
• On account of the new sugar the substance is
  called deoxyribonucleic acid or DNA

• Levine also thought that these nucleotides
• Adenine
• Thymine
• Cytosine and
• Guanine
• All occur in equal amounts

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Frederick Griffith Worked with Smooth (lethal)
and Rough (harmless) cells of pneumonia and
mice. Found that a transforming principal exists
that can alter traits in bacteria and that has an
effect that is later heritable. The Transforming
Principal is unknown
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Henry Dawson Refined Griffiths findings and
showed that there was a chemical inside the dead
smooth cells and that that acted as a
transforming principal. It could alter a rough
cells traits to make it smooth cells. As well
these new smooth cells are able to pass on this
new trait to their next generation
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X
Avery Oswald First to show that DNA was the
Transforming principal that everybody was looking
for and not protein. BUT World was not convinced
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Hershey and Chase Through work with bacteria and
viruses they prove without a doubt that DNA and
not protein carries the information that is
needed for reproduction and that genes are made
from DNA
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• Chargaff
• Finds that Levine is wrong in that there are not
  equal amounts of the nucleotides
• But
• No matter the species the amount of Adenine
  always to the amount of Thymine.
• Amount of Guanine is to the amount of Cytosine