BIO 30 names

2nd exam

1860 Friedrich Miescher

• while characterizing proteins from pus cells

• isolated a molecule from the nucleus and called it “nuclein” (DNA in the 1930s)

1866 Ernst Haeckel

• discovered that the most obvious cellular component of the cell is the nucleus

1895 Edmund Wilson

using staining technique to study karyokinesis of ovum

• important nuclear element handed from cell to cell: DNA
- Ascaris ova

1928 Frederick Griffith (US Medical Officer)

• transformation experiment using Streptococcus pneumoniae

• avirulent (R) strain was transformed to virulent (S)

• declared the presence of transforming principle

1944 Oswald Avery, Colin MacLeod and Maclyn McCarty

• Physician-Scientists

• identified the transforming principle (TP) as DNA 16

• when TP was treated with proteinases and RNases

➢ transforming ability is retained. ➢ therefore TP is not protein nor RNA)

1952 Alfred Hershey and Martha Chase

• proved that DNA is the genetic material of the bacterial viruses (phages)

• DNA is labeled with 32

• protein coat is labeled with 35S. 23

• famous blender experiment

• separates phages from bacteria after infection

• this proved: DNA is injected into the cell while the protein coat remained outside.

1952 Norton Zinder, Joshua and Esther Lederberg

• Nobel Prize for genetic research in 1958 (Joshua)

• performed transduction experiment in Salmonella typhimurium

Francis Crick

➢ 1938 B.S. Physics Univ. College London

➢ 1940-47 involved in the development of radar and magnetic mines

- 1947 started to work in Biophysics at Cambridge

- 1949-53 did his Ph.D. on X-ray studies on proteins

James D. Watson

- child prodigy from Chicago

- 1947 B.S. Biology Univ. of Chicago

-1950 Ph. D. in Microbiology Univ. of Indiana

- did labeling of phage DNA at Denmark

- 1951 moved to Cambridge and shared office with Crick

Maurice Wilkins

➢ Ph.Din Physics

➢ Manhattan project (1939-46)

➢ Assistant Director of Medical Research at Kings College, London

➢ Worked on X-ray diffraction of DNA

Rosalind Franklin

- expert on X-ray diffraction technique

- joined Kings College in 1951

- worked on X-ray diffraction of DNA

-The unsung hero of the DNA

1951-53 Rosalind Franklin, Gosling and Maurice Wilkins

➢ helical DNA structure

➢ sugar and phosphate outside

➢ nucleotides inside

1953 James Watson and Francis Crick

Cambridge University, UK

- triple helix

- phosphate in the center

1950s Linus Pauling

-Chemist, California Institute of Technology

- triple helix DNA

John Griffith

- nucleotides are flat, one on top of another

- possibility of A=T, C=G pairing

- Crick saw the importance of specific pairing in replication.

Erwin Chargaff

- purine-pyrimidine ratio 1:1 (Chargaff’s rule)

Jerry Donohue

- H in the bases can change its position.

- possibility for H bonding

Watson, Crick and Wilkins

Nobel Prize winner in 1962 for Configuration of DNA

1958 Matthew Meselson and Franklin Stahl

- semi-conservative

- grew E. coli in 15N and 14N

- isolated the DNA

- centrifugation in caesium chloride