DNA Timeline By 13voelkl Feb 12, 1953 DNA is founded. DNA is in the shape of a double helix with antiparallel nucleotide chains and specific base pairing. Feb 12, 1958 DNA replication is semi-conservative. Feb 12, 1959 Messenger RNA is the intermediate between DNA and protein. Feb 12, 1966 The genetic code is cracked by a number of researchers using RNA homopolymer and heteropolymer experiments as well as tRNA labeling experiments. Feb 12, 1970 The first restriction enzyme is purified by Hamilton Smith. Period: Feb 12, 1972 to Feb 12, 1973 Recombinant DNA is first constructed by Cohen and Boyer. Feb 12, 1977 DNA sequencing technology is developed by Fred Sanger. Feb 12, 1986 PCR is developed by Kary Mullis. Period: Feb 12, 1990 to Feb 12, 1999 Genome projects are begun. Period: Feb 12, 1990 to Feb 12, 1999 DNA microarrays are invented by Pat Brown and colleagues. Feb 12, 1995 Automated sequencing technology allows genome projects to accelerate. Period: Feb 12, 1996 to Feb 12, 1997 The first cloning of a mammal (Dolly the sheep) is performed by Ian Wilmut and colleagues, from the Roslin institute in Scotland. Feb 12, 2000 The Drosophila genome is completed. The Arabidopsis genome is completed. The human genome is reported to be completed. Feb 12, 2001 The sequence of the human genome is released, and the "post-genomic era" officially begins. Feb 12, 2009 Controversies continue over human and animal cloning, research on stem cells, and genetic modification of crops.