Since the early 1970s, when recombinant DNA technology was first developed, there has been a veritable explosion of knowledge in the biological sciences. Since that time, with the advent of PCR, chemical DNA synthesis, DNA sequencing, monoclonal antibodies, directed mutagenesis, genomics, proteomics, and metabolomics, our understanding of and ability to manipulate the biological world have grown exponentially. When the first edition of Molecular Biotechnology: Principles and Applications of Recombinant DNA was published in 1994, nearly all of the transgenic organisms that were produced included only a single introduced gene. Just 15 years later, it is not uncommon for researchers to engineer organisms by modifying both the activity and the regulation of existing genes while at the same time introducing entire new pathways. In 1994, only a handful of products produced by this new technology were available in the marketplace. Today, molecular biotechnology has given us several hundred new therapeutic agents, with many more in the pipeline, as well as dozens of transgenic plants. The use of DNA has become a cornerstone of modern forensics, paternity testing, and ancestry determination. Several new recombinant vaccines have been developed, with many more on the horizon. The list goes on and on. Molecular biotechnology really has lived up to its promise, to all of the original hype.
It has been estimated that worldwide there are currently several thousand biotechnology companies employing tens of thousands of scientists. When the exciting science being done at universities, government labs, and research institutes around the world is factored in, the rate of change and of discovery in the biological sciences is astounding. This fourth edition of Molecular Biotechnology, building upon the fundamentals that were established in the previous three editions, endeavors to provide readers with a window on some of the major developments in this growing field in the past several years. Of necessity, we have had to be highly selective in the material that is included in this edition. Moreover, the window that we are looking through is moving. This notwithstanding, we both expect and look forward to the commercialization of many of these discoveries as well as to the development of new approaches, insights, and discoveries.