1961โ1965 โ Genetic code was delineated, responsible for translating the connection between DNA and proteins: โข Genetic code (DNA and RNA) was revealed to be generally universal in all living things. โข In the genetic code, the four RNA nucleotides (two purines โ adenine and guanine and two pyrimidines โ uracil and cytosine) in varied triplet codes (over 60 triplets) had a direct relationship to the 20 amino acids in determining the structure of proteins. โข The multifaceted and interrelated roles of several RNA species, that is, messenger RNA, ribosomal RNA, and transfer RNA, were elucidated in the transcription and translation processes, resulting in nuclear DNA codes being transformed into the production of proteins in cell cytoplasm. 1963 โ The peptide insulin was synthesized. 1964 โ Reverse transcriptase enzyme was discovered for creating in reverse order, DNA from RNA. 1970 โ Hamilton Smith discovered restriction enzyme, responsible for cutting DNA into fragments, permitting genetic manipulation. 1971 โ The biotech company Cetus was founded. 1972 โ DNA ligase was used to recombine DNA fragments, further permitting genetic manipulation. 1972 โ Dr. Paul Berg combined genes isolated from different organisms (mammalian or bacteria) into a hybrid DNA molecule. 1973 โ Drs. Stanley Cohen (Stanford University) and Herbert Boyer (University of California, Berkley) created the first recombinant DNA experiment, inserting a DNA molecule (fragment) into another cellโs DNA with replication/cloning of DNA. 1974 โ The National Institutes of Health (NIH) in the United States formed the Recombinant DNA Advisory Committee for oversight of recombinant genetic research. 1975 โ Monoclonal antibody technology was developed by Drs. Georges Kohler, Neils Jerne, and Cesar Milstein through hybridoma cell development, that produce antibodies versus specific antigens and demonstrating hybridomas are immortal. 1976 โ The biotech company Genentech was founded. 1977 โ DNA sequencing techniques were developed, permitting accurate sequencing of genes, separately by both Dr. Walter Gilbert in the United States and Dr. Frederick Sanger in England. 1977 โ The human peptide for growth hormone, somatostatin, was produced in a genetically engineered bacteria, a first for cloning of a human protein or peptide with a human gene inserted in a nonhuman organismโs DNA. |