The Story of DNA
--- History of Molecular Biology
“History Teaches Everything, Including the Future.”
--- Alphonse de Lamartine
Genetics
Biochemistry
Cell biology
Microbiology
Virology
…
Overview of the History of Molecular Biology
 1929 – the chemical components of DNA
 1940 – the relationship between genes and proteins
 1944 – Genes are made up of DNA
 1953 – the double helical structure of the DNA molecule
(Watson and Crick)
 1957 – the “Central Dogma” and the “sequence
hypothesis” (Crick)
 1958 – the mechanism of DNA replication
 1961 – the hypothesis of the messenger RNA (mRNA)
 1961 to 1965 – the genetic code was deciphered
……
 1970s to 80s – DNA cloning, sequencing and genetic engineering
 1990s to 2000s – genome sequencing and functional study of genes
Overview of the History of Molecular Biology
Discovery of
DNA
1930
Genes and
DNA
1940
1950
DNA cloning and
genetic
engineering
DNA - RNA protein
1960
1970
1980
Genome era
1990
2000
The search of genetic material
Discovery of
DNA
1930
Genes and DNA
1940
DNA cloning and
genetic engineering
DNA - RNA - protein
1950
1960
1970
• The discovery of DNA
-
Hofmeister (1848): discovery of
chromosomes
Miescher (1868): “nuclein” = DNA + protein
• Chromosome theory of inheritance
-
Mendel (1865): Laws of inheritance
Morgan (1910): Genes are on chromosomes
• Who carries genetic material,
DNA or proteins?
1980
Genome era
1990
2000
How did people know that DNA carries
genetic information?
Discovery of
DNA
1930
Genes and DNA
1940
1950
DNA cloning and
genetic engineering
DNA - RNA - protein
1960
1970
1980
Genome era
1990
2000
Avery, Macleod and McCarty’s experiment (1943)
http://www.dnaftb.org/dnaftb/17/animation/animation.html
Avery’s Experiment on Pneumococcus:
• A) What was the original observation that Avery
made in test tubes?
• B) List two hypotheses based on the observation
(doesn’t matter if they are right or wrong).
• C) What predictions would you make based on each
of the hypotheses?
How did people know that DNA carries
genetic information?
Discovery of
DNA
1930
Genes and DNA
1940
1950
DNA cloning and
genetic engineering
DNA - RNA - protein
1960
1970
1980
Genome era
1990
2000
Avery, Macleod and McCarty’s experiment (1943)
http://www.dnaftb.org/dnaftb/17/animation/animation.html
The Double Helix
Discovery of
DNA
1930
Genes and DNA
1940
1950
DNA cloning and
genetic engineering
DNA - RNA - protein
1960
1970
1980
Genome era
1990
2000
 Crick and Watson: theoretical model
 Wilkins and Franklin: X-ray diffraction
 First accurate model of DNA's
molecular structure (1953)
 Nobel Prize, 1962
"Why You Are You. Nearer Secret of
Life." --The News Chronicle of London
Watson
Crick
Wilkin
Franklin
Rosalind Franklin: The Dark Lady of DNA
 Rosalind Franklin (1920-1958)
 A British Biophysicist
 Specialized in X-ray
crystallography
 King’s College, London (19511953):
- Worked with Maurice Wilkin and
Raymond Gosling
 Form A and B of DNA
 Photograph 51
”The Eighth Day of Creation: Makers of the
Revolution in Biology“ by Horace Freeland
Judson
From DNA to Proteins
Discovery of
DNA
1930
Genes and DNA
1940
DNA cloning and
genetic engineering
DNA - RNA - protein
1950
1960
1970
1980
Genome era
1990
2000
Reverse
transcriptase
 1957 – the “Central Dogma” (Crick)
 1958 – the mechanism of DNA replication
 1961 – the hypothesis of the messenger RNA
 1961 to 1965 – the genetic code was deciphered
Howard Temin
(Nobel Prize 1975)
The Golden Age of Molecular Biology
Discovery of
DNA
1930
Genes and DNA
1940
DNA cloning and
genetic engineering
DNA - RNA - protein
1950
1960
1970
1980
Genome era
1990
2000
 1969: First gene in bacterial DNA isolated
 1970: First synthetic (artificial) gene
 1973: First successful DNA cloning experiment
 1977: DNA is sequenced
Har Gobind Khorana
(Nobel Prize 1968)
 1978: The first human gene is cloned – insulin
 1982: Genetically-engineered insulin is approved for use
 1985: PCR (Polymerase Chain Reaction) is invented
The Golden Age of Molecular Biology
Discovery of
DNA
1930





Genes and DNA
1940
1950
DNA cloning and
genetic engineering
DNA - RNA - protein
1960
1970
1980
Genome era
1990
2000
1996: First genome sequenced – S. cerevisae (yeast)
1997: Bacteria E. coli genome sequenced
1998: C. elegans (worm) sequenced
2000: Drosophila (fruit fly) sequenced
2002: Mouse sequenced

2001: First draft sequences of the human genome are
released (Human Genome Project)

2003: Completion of the mapping of the genes in the
human genome
Fred Blattner
What can we do with DNA?
 Genetic engineering
- Use model organisms to study
genes and functions
- Make transgenic organisms
 Applications for human
- Forensics, paternity testing
- Genetic diagnosis and prevention
of diseases (Genetic counseling)
- Gene therapy
…
DNA and The Revolution in Personalized
Medicine
 Your life depends on the secret of
your DNA…
 Personalized Medicine
- Genetic screening for prevention
(newborn screening, carrier screening,
maternal screening, Pre-implantation Genetic
Diagnosis (PGD))
- Risk prediction
- The right drug at the right dose for the
right person
Fields Related to Modern Molecular biology
 Molecular genetics
 Genomics
 Cell Biology
 Developmental
Biology
 Bioinformatics
 Population and evolutionary biology
 Biophysics and
Structural Biology
Next class:
Case Study: The Human Genome
Project and Designer Baby
Discussion of Molecular biology
research groups on campus – What
do they do and why?