The months in early 1973 were a period of almost unbelievable excitement. The strategy worked even better than we could have expected and on most days there was a new results and a new high. Plasmids were isolated at Stanford, transported to UCSF where they were cut by eco R1 and analyzed and then transferred back to Stanford where the DNA fragments were joined and the plasmids were reintroduced into bacteria. Annie Chang, who was then a research technician in my laboratory, did many of the plasmid DNA isolations and bacterial transformations. Since Annie lived in San Francisco, California she also carried our precious DNA samples between the two labs almost daily. Bob Helling who was on sabbatical leave in Boyers lab did some of the DNA analyses.
Many were the times when I wished that the bacteria would grow faster so that the next result could be obtained sooner. In May 1973 a manuscript describing our results was prepared for submission to the proceedings of the National Academy of Sciences. This paper which was published in November of that year forms the basis for Stanford/University of California patent that underlies much of modern biotechnology.
Were the practical implications of this basic research and its potential applications for biotechnology apparent to us? You bet they were. However, the demonstration that fragments of DNA from E.coli plasmids could be cloned in their natural host by linking them to a plasmid replication regions didn't necessarily mean that DNA could be propagated in a foreign host using the same methods. In fact, it had long been believed that biological barriers such as the restriction modification systems Herb Boyer will be talking about, would prevent DNA transfer between all but the most closely related species.
While the first scientific report of DNA cloning was in press, Chang and I found that DNA could be transferred between unrelated bacteria by the cloning procedures. Shortly afterward a second collaboration between Boyer's lab and mine with the participation of John Morrow at Stanford and Howard Goodman at UCSF showed that DNA from even animal cells could be propagated in bacteria, again using the same overall approach. Chang and I together with Robert Schimke at Stanford later showed that bacteria containing DNA transplanted from a mouse could produce a biologically active mouse cell protein, thus demonstrating that molecular manufacturing plants were in fact practical.
  
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