surprising direction of discovery led to fundamental ambiguities concerning the scope of molecular biology in relation to other disciplines. Bacteriologists, organic chemists, geneticists, and classical biochemists5 all contributed to the growing body of tools, techniques, and theory. Paul Berg, one of the most innovative researchers within the field and a biochemist by training, argues that molecular biologists were united by similar beliefs about the proper level at which to understand cell behavior: "Someone who would have called themselves a molecular biologist … would want to understand the phenomena at the molecular level" (telephone interview with Paul Berg, Professor of Biochemistry, Stanford University, February 17, 1993). This approach necessitated asking questions of a more fundamental nature than those asked within much of the mainstream of classical biochemistry. While perhaps providing the advantage of analytical depth and rigor, pre-1970s molecular biology suffered from tools that were inadequate for seriously studying eukaryotic (higher) organisms. Thus, the whole of biochemistry, much of it focused on "the characterization of metabolic pathways … of the more numerous and immediately useful proteins" (Kenney, 1986, p. 12), was affected but not transformed by molecular genetics. This distinction held as long as understanding of the physiological events of eukaryotes could not be greatly enhanced through the use of molecular genetic approaches.

After 1970, critical advances in technique, instrumentation, and theory overcame many of the barriers that had slowed the adoption of molecular genetics. The most public and startling of these advances was the gene-splicing technique pioneered by Stanley Cohen and Herbert Boyer in 1973. Along with work by Jackson, Symons, and Berg, the potential to manipulate—to change—the genetic code and subsequent protein production of an organism became feasible through use of restriction enzymes6 developed by Boyer (Johnson, 1983). This technique "has allowed for the first time the analysis of individual eukaryotic genes as well as the study of the organization of genetic information in higher organisms," as well as "enabled modification of the genetic makeup of bacteria and unicellular eukaryotic organisms so as to render them capable of producing gene products encoded by the DNA of higher eukaryotes" (Cohen, 1982, p. 21). The Cohen-Boyer technique had a broad effect on biology and biochemistry. Not only did it aid in the resolution of long-standing questions, it opened up the possibility of asking fundamentally new questions. Not surprisingly, the fundamental novelty of the technique led to serious questions of ethics and safety. Perhaps a bit more


The definition and boundaries of each of these disciplines have changed over time, but the textbook definition or the relative scope of each has not changed nearly as much as that of molecular biology.


Restriction enzymes are the critical material in "cutting" up genetic material for the purpose of extracting specific DNA strands. These strands are then spliced into plasmids for the purpose of insertion into bacteria.

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