1880
August Weissmann states genetic information of a cell diminishes with each cell division.
1902
Walter Sutton proves chromosomes hold genetic information.
1902
Hans Spemann divides a Salamander embryo in two and shows early embryo cells retain all the genetic information necessary to create a new organism.
1928
Hans Spemann performs first nuclear transfer experiment.
1938
German scientist Hans Spemann proposes a "fantastical experiment" to transfer one cell's nucleus into an egg without a nucleus, the basic method that would eventually be used in cloning.
1944
Oswald Avery discovers genetic information is carried by the nucleic acids of cells.
1952
Briggs and King clone tadpoles.
1953
Watson and Crick find the structure of DNA.
1958
F.C. Steward grows whole carrot plants from carrot root cells.
1962
John Gurdon clones frogs from differentiated cells.
1963
J.B.S. Haldane coins the term 'clone.'
1966
Establishment of the complete genetic code.
1967
Enzyme DNA ligase isolated.
1969
Shapiero and Beckwith isolate the first gene.
1970
First restriction enzyme isolated.
1972
Paul Berg creates the first recombinant DNA molecules.
1973
Cohen and Boyer create first recombinant DNA organisms.
1977
Karl Illmensee claims to have created mice with only one parent.
1978
The release of David Rorvik's book, In His Image: The Cloning of a Man, sparks a worldwide debate on cloning ethics.