History and discovery

Discovery of Nucleic Acids

1869

Friedrich Miescher
Nucleic acids were discovered by Friedrich Miescher in 1869, when he isolated a substance from the cell nucleus which he called nuclein (now known as DNA).

Discovery of DNA Components

1910

Phoebus Levene
Determined the components of DNA (Adenine, Guanine; Thymine, Cytosine, Deoxyribose Phosphate).

Transformation experiment

1928

Frederick Griffith
Reported the first demostration of bacterial transformation.
He used two strains of Streptococcus (type S "virulent" and Type R "non-virulent").

Determined the cause of the transformation experiment

1944

Avery, MacLeod and McCarty resolts the question with Type R + Heat-killed smooth with two grups: with protease - mouse dies and with DNAse - mouse lives. To sume up, the DNAse is the cause of transformation.

Double Helix

1950

Watson and Crick wrote a paper describing the DNA as a double helix with sugars and phosphates at center and the nucleobases facing the outside.
Is incorrect model.

Triple Helix?

1952

Linus Pauling and Robert Corey proposed a triple helix and is incorrect model.

Hershey-Chase Experiments

1952

Afred Hershey and Martha Chase
The bacteriophage is a virus that infects a bacterias. So they studied how bacteria behaved depending on whether the protein or DNA was infected. And they discovered that genetic material is in DNA.

Counting nucleobases

1952

Erwin Chargaff
Examine the abundance of the nucleobases with paper chromatography and UV spectroscopy.
Discoverd the % of the Adenine an Thymine are the same and Cytosine and Guanine too.

Double Helix DNA

1953

Francis Crick, James Watson, Maurice Wilkins and Rosalind Franklin
They will discover a photo of the double helix and created the current model.

Noble Prize in Physiology or Medicne

1962

Crick, Watson and Wilkins
They win the Nobel Prize for their discoveries concerning the molecular structure of nucleic acids.