If we take all organisms whose genetic information has been changed by human activity and among them select only those, whose changes could not even theoretically occur naturally, we will formally speak of GMOs – organisms created by methods of recombinant DNA technology and genetic engineering. This approach, compared to the hard-to-predict and slow process of breeding, allows us to make a precisely planned intervention in the genetic material of the organism, with a relatively easy-to-predict result. In reality, the creation of GMO starts with the isolation of DNA from one organism and identification of a gene that is useful to us (economically or scientifically). Afterwards, we multiply this gene, separate it from the rest of the DNA and connect it with the carrier DNA (e.g., part of a virus or plasmid), which will facilitate its incorporation into the genetic material of another organism. In the laboratory, it is possible to insert such recombinant DNA (it is a combination of the carrier DNA and the gene that we want to transfer) into the cell of the host organism, where it merges with the original genome (Figure 17.3).
In 1973, the first GMO bacterium was created, which included a gene for resistance to the antibiotic kanamycin (originating from another type of bacterium). In the following years, it was possible to modify the DNA of a mouse in a similar way (1974) or to insert an antibiotic resistance gene into the genome of a tobacco plant (1983). As soon as it became clear that changing the genetic information of various organisms is possible using the same basic set of tools, biotechnologists began to come up with ideas for modifying individual economically important organisms. What was the purpose of these modifications? The same thing that was central to every new biotechnology - to get food, medicine, and other commodities in larger quantities, faster and easier than ever before.