The words biotechnology, genetic engineering, and molecular biology have engendered very diverse responses from scientists, and the public. Whether one's reaction to these terms is awe, fear, doubtfulness, or ambivalence, these technologies justify the response, for they are probably the most powerful scientific biological tools in existence today. They are not, however, new tools that have suddenly burst upon us. Rather, as with most new tools, science has been slowly developing them over a number of years. To put them in perspective, observe the events and the spans that have occurred during their development. As early as 1920-1940, scientists were attempting to artificially manipulate genes through x-ray mutations and colchicine. It was during this period that the presence of plant growth substances was established. From 1940-1950 scientists determined that DNA was the basis of inheritance, elucidated its structure and began studies to show that DNA of one organism could be transferred to another organism. The mechanism of bacterial plasmid transfer was understood. Notably, the crown gall disease of plants, Agrobacterium tumefacieums, came under scrutiny. Between 1960 and 1970 tissue culture efforts led to the demonstration that plant cells were totipotent, i.e. an entire plant could be regenerated from a cell. As you can see, the parts were coming together. There was lacking, however, the ability to manipulate the parts. This came about in the 1970-1980 period. This was a very exciting period. Enzymes were discovered that could cut and splice DNA at very specific sites in its structure, allowing the first recombinant DNA work. The study of the crown gall disease led to the discovery that the bacteria could insert its own DNA into the plants DNA during infection. With this eventful discovery, it took little to pursue the possibilities of using recombinant DNA techniques to splice foreign DNA into the crown gall organisms DNA and then allow the bacterium to Insert that DNA into the DNA of the plant along with its own DNA. Thus, the ability to move genes not only between species but between phyla was achieved. It was not until 1983 that we really began to understand these possibilities and in 1986 it would be clearly demonstrated that recombinant DNA techniques would be a powerful tool in crop improvement by the first field test of a crop plant modified by recombinant DNA.

Recombinant DNA techniques are really those of a 'cut and paste' operation using restriction and ligation enzymes to delete and add pieces of DNA.