Jenner inoculates a child with a viral vaccine to protect him from smallpox.

1830

          Proteins are discovered.

     1833

          The first enzymes are isolated.

     1855

          The Escherichia coli (E. Coli) bacterium is discovered. It later becomes a major research, development and

          production tool for biotechnology.

1863

          Mendel, in his study of peas, discovers that traits are transmitted from parents to progeny by discrete,

          independent units, later called genes. His observations laid the groundwork for the field of genetics.

1869

1869: Swiss scientist Friedrich Miescher discovers that the nuclei of pus cells contain an acidic substance, which he names "nuclein." He later finds that nuclein comprises a protein and a sugar and phosphate compound to which the name nucleic acid -- subsequently changed to deoxyribonucleic acid (DNA) -- is given.

DNA (first called "nuclein") is identified by Friedrich Miescher as an acidic substance found in cell nuclei. The significance of DNA is not appreciated for 70 years.

          Miescher discovers DNA in the sperm of trout.

1879

          Fleming discovers chromatin, the rod-like structures inside the cell nucleus that later came to be called

          chromosomes.

1902

Sutton Pointed out the interrelationships between cytology and Mendelism, closing the gap between cell morphology and heredity.

1910

Thomas Morgan's experiments with the fruit fly (Drosophila) reveal some characteristics are sex-linked: Confirms genes reside on chromosomes

1911

          The first cancer-causing virus is discovered by Rous.

1940

          American Oswald Avery demonstrates that DNA is the "transforming factor" and is the material of genes

1941

One gene encodes one protein, as described by Beadle and Tatum.

George W. Beadle (1903-1989) of the U.S. and Edward L. Tatum (1909-1975) of the U.S. discovered that genes control the production of enzymes.

George Beadle and Edward Tatum develop the idea that each gene controls the development of one enzyme.

George W. Beadle and Edward L. Tatum show how genes direct the synthesis of enzymes that control metabolic processes

1946

          Discovery that genetic material from different viruses can be combined to form a new type of virus, an example of

          genetic recombination

Discovery that genetic material from different viruses can be combined to form a new type of virus, an example of genetic recombination

1947

          McClintock discovers transposable elements, or "jumping genes," in corn.

1949

          Pauling shows that sickle cell anemia is a "molecular disease" resulting from a mutation in the protein molecule

          hemoglobin.

1950

	Erwin Chargaff discovers regularity in proportions of DNA bases for different species

1953

          Nature publishes James Watson's and Francis Crick's manuscript describing the double helical structure of DNA,

          which marks the beginning of the modern era of genetics.

1955

1955-61: Further work in Britain and the United States establishes DNA's role in making proteins and how the molecule self-replicates and lays the foundation for gene sequencing

1956

          The fermentation process is perfected in Japan. Kornberg discovers the enzyme DNA polymerase I, leading to an

          understanding of how DNA is replicated.

1958

          Sickle cell anemia is shown to occur due to a change of a single amino acid.

1959

Japanese scientists make a discovery which will be vital in the development of genetic engineering. They find resistance to antibodies in Shigella dysenteriae is passed from one bacterium to another by small circles of DNA known as plasmids, separate from the normal DNA.

1960

          Exploiting base pairing, hybrid DNA-RNA molecules are created.

          Messenger RNA is discovered.

1963

New wheat varieties developed by Norman Borlaug increase yields by 70 percent.

1964

Charles Yanofsky and colleagues prove sequence of nucleotides in DNA correspond exactly to the sequence of amino acids in proteins

1966

          The genetic code is cracked, demonstrating that a sequence of three nucleotide bases (atriplet mRNA condons or codons) determines each

          of 20 amino acids.

1967

Charles Caskey, Richard Marshall and Marshall Nirenberg show that identical messenger RNA is used to form identical amino acids in bacteria, toads and guinea pigs, leading to the suggestion that the genetic code is a universal information system for all life forms.

  1969

          An enzyme is synthesized in vitro for the first time.

First gene in a piece of bacterial DNA isolated. The gene plays a role in the metabolism of sugar

1969 A team at Harvard Medical School led by Jonathan Beckwith isolates the first gene, specifically, abacterial gene whose protein product is involved in sugar metabolism

1970

Werner Arber, a Swiss scientist, makes a discovery which has far reaching effects for genetic engineering. He finds that bacteria defend themselves against viruses by cutting the virus DNA using special restriction enzymes. (These enzymes are now widely used in the new DNA technologies.)

          Specific restriction nucleases are identified, opening the way for gene cloning.

          First complete synthesis of a gene

Norman Eorlaug receives the Nobel Peace Prize (see 1963).
Discovery of restriction enzymes that cut and splice genetic material, opening the way for gene cloning.

Smith and Wilcox Isolated the first restriction enzyme, HindII, that could cut DNA molecules within specific recognition sites.

1971

          Discovery of restriction enzymes that cut and splice genetic material

Daniel Nathans and Hamilton Smith develop enzymes which break DNA at specific sites – another step towards genetic engineering.

1972

Berg produces first recombinant dna molecules

While studying isolated genes, Berg developed a method for splitting DNA molecules at selected sites, attaching segments of the molecule to the DNA of a virus, and then introducing it into bacterial or animal cells. The foreign DNA was incorporated by the host, which then produced proteins not ordinarily found in the host. This joining of two pieces of DNA from different species is called recombinant DNA. The process is a cornerstone of genetic engineering.

1973

Stanley Cohen and Herbert Boyer show that DNA molecules can be cut with one type of enzyme, joined together again with another type and reproduced by inserting

them into the bacteria E. coli. This is the beginning of the science of genetic engineering.

          Stanley Cohen and Herbert Boyer perfect genetic engineering techniques to cut and paste DNA (using restriction

          enzymes and ligases) and reproduce the new DNA in bacteria.

First genetic engineering experiment: insertion of a gene from an African clawed toad into a bacterium

Chang and Cohen Showed that a recombinant DNA molecule can be maintained and replicated in E. coli.

Scientists successfully transfer DNA from one organism into another, making a 'recombinant organism'. Viral DNA is added to a bacterium.

1974

          The National Institutes of Health forms a Recombinant DNA Advisory Committee to oversee recombinant genetic

          research.

1975

          Asilomar Conference (moratorium on genetic engineering research).

          The first monoclonal antibodies are produced.

1976

          The tools of recombinant DNA are first applied to a human inherited disorder.  

          Yeast genes are expressed in E. coli bacteria.  

          DNA sequencing discovered; first working synthetic gene.

The sequence of DNA base pairs for a specific gene is determined