or normal human reticulocytes. The rabbit ribosome cell-free system was able to produce normal human globin from normal human mRNA, sickle cell globin from sickle cell mRNA, and the abnormal alpha/beta globin chain abnormality of thalassemia from thalassemia mRNA. Microinjection of globin DNA into mammalian cell nuclei As a first approach for developing a human gene therapy procedure, standard microinjection techniques were modified to permit the injection of DNA plasmids into the nucleus of mammalian cells. Human globin genes were microinjected into mouse fibroblasts and into mouse oocytes and shown to express human globin mRNA. Development of retroviral gene therapy vectors Microinjecting a few non-stem cells was clearly not an efficient procedure for a clinical protocol. In 1984, Anderson published a major review in Science in which he analyzed the "Prospects for Human Gene Therapy" and concluded that the most promising approach was to use retroviral vectors as a delivery vehicle. He immediately established a close, long-term collaboration with one of the top retroviral vector scientists: Eli Gilboa, then at Princeton. Together they developed vectors that could efficiently carry a gene package into mouse or human cells in culture. The most efficient vector, N2, carrying a neomycin resistance gene, was used to transduce mouse bone marrow cells. The N2-transduced cells were injected into lethally irradiated mice where they repopulated the marrow. The presence and expression of the N2 vector could be detected in the repopulated mouse bone marrow cells by testing for the resistance of the marrow cells to the toxic antibiotic neomycin. Once the procedure was working successfully in mice, successful studies were done in non human primates. In addition, extensive safety studies were done in the vector transduced animals. Successful gene therapy of a human patient Attempting to perform gene therapy by inserting recombinant DNA into a human being was extremely controversial after an illegal attempt was made in 1980. Anderson, together with bioethicist John Fletcher, set the ethical standard for this type of clinical protocol in his 1980 article in The New England Journal of Medicine entitled: "Gene Therapy In Human Beings: When Is It Ethical To Begin?" An extensive regulatory process was established during the late 1980s, including the creation of the Human Gene Therapy Subcommittee as a first round of regulatory oversight. Only after approval by that formal public governmental review did the gene therapy clinical protocol move on for review by the Recombinant DNA