DNA Scientists

Frederick Griffith

British bacteriologist known for discovering the transforming principle in bacteria, which identified DNA as the carrier of genetic information.

S Strain

The disease-causing strain of bacteria identified by Griffith, which had smooth colonies and caused pneumonia.

R Strain

The harmless strain of bacteria identified by Griffith, which had rough edges and did not cause disease.

Oswald Avery

Canadian-born American bacteriologist who established that DNA is the substance responsible for heredity.

Hershey and Chase experiment

Confirmed DNA as genetic material by studying bacteriophages and showing that DNA, not protein, carries genetic information.

Erwin Chargaff

Biochemist who discovered Chargaff's rules, stating that the amount of adenine equals thymine, and cytosine equals guanine in DNA.

Chargaff's rules

The principle that in DNA, the quantity of adenine equals that of thymine, and the quantity of cytosine equals that of guanine.

Rosalind Franklin

British chemist known for her X-ray diffraction work which provided essential clues to the structure of DNA.

X-ray diffraction

A technique used by Rosalind Franklin to analyze the molecular structure of DNA.

Maurice Wilkins

British physicist whose X-ray diffraction studies were crucial in determining the structure of DNA.

Watson and Crick

American molecular biologist and British physicist who were credited with the discovery of the double helix structure of DNA.