1. The Genetic Timeline

2. 1868
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

3. 1910
Phoebus Levine
Over time Meischer’s nuclein was found to be a major part of chromosomes
Through hydrolysis Nuclein contained
Unique sugar called deoxyribose
Phosphate
4 kinds of nitrogen bases

4. Nitrogen-containing bases
Nuclein
Deoxyribose (sugar)
Phosphate
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Hydrolysis

5. Levine figured that each nitrogen base was attach to a sugar
Each sugar was then attached to a phosphate group P S N
This arrangement of molecules was called a nucleotide and is specifically named for the nitrogen base it contains

6. 1910 Levine also thought that these nucleotides Adenine Thymine
Phoebus Levine
Meischer’s 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

7. 1927
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

8. 1931
Henry Dawson
Refined Griffith’s 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

9. X
1944
Avery Oswald
First to show that DNA was the Transforming principal that everybody was looking for and not protein.
BUT
World was not convinced

10. 1952
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

11.
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