Biotechnology is a new science that includes genetic engineering based on the use of recombinant DNA. Thanks to the restriction enzymes, real "molecular scissors," a fragment of DNA can be cut and stitched up elsewhere. This is possible because these enzymes create DNA fragments with cohesive ends that can stick together perfectly. In this way, it is possible to incorporate a gene into a vector, often a plasmid, which can be inserted into another cell, even of another species. This will then be able to express the exogenous, or foreign, gene. So this subject is the amalgamation of Recombinant DNA technology and genetic engineering.
For example, a eukaryotic gene with introns, i.e., regions that do not code, inserted in a prokaryote, will not synthesize the correct protein. The reverse enzyme transcriptase is used to solve this problem, which can create a complementary DNA string (cDNA) to the mature mRNA, which has already lost introns.
The cDNA is then inserted into the vector, which will be expressed in the prokaryote.
Biotechnology aims to use cells as "factories," able to perform the work for which they have been reprogrammed and exploit some peculiar characteristics. Applications can indeed be used in several fields:
Medical - synthesis of drugs, vaccines, and anticancer drugs (human insulin was the first molecule produced by a recombinant bacterium), artificial fertilization, diagnosis, gene therapies.
Environmental/agronomic - wastewater treatment (bioremediation), plants resistant to adverse conditions (parasites, decomposition, pesticides, cold, drought).
Industrial - production of biofuels (bioethanol, biodiesel), vitamins, and enzymes, used in sectors such as cosmetics, textiles, and food.
The most used organisms are the bacterium Escherichia coli, which lives in the human intestine, and the yeast Saccharomyces cerevisiae, the typical bread yeast, which are readily manipulated, thanks to the biochemical, biomolecular, and genetic knowledge acquired so far. Furthermore, these organisms replicate quickly and have low nutritional needs. This makes them perfect for growth in bioreactors, devices used as containers for the recombinant organism.
Biotechnological studies have made it possible to obtain critical technologies that are widely used in laboratories worldwide.
The technique called PCR, for example, can synthesize in a short time many copies of a gene or a fragment of it starting from even a single molecule. The scientific police also use this method for DNA testing, proof of legal value in the trial. Furthermore, it is now possible to sequence a genome, that is, to "read" the DNA of each individual. This technique can have significant preventive results in early diagnosis and the study of predisposition to some diseases.
The not distant goal is to create a fully synthetic genome, to be inserted into an organism in place of the original. By doing so, the cell will only do what is written in this new DNA, it being its "instruction book." In a recent experiment, Professor Craig Venter, a world-renowned American scientist, succeeded in inserting a completely artificial genome into a bacterium devoid of its DNA. This new cell is the first step towards creating new forms of life capable of fulfilling the roles that man can exploit for his well- being and the environment, such as the production of drugs or the degradation of pollutants.