Abstract

The rapid sequencing of entire genomes based in large measure on a DNA cloning procedure, the polymerase chain reaction (PCR), has opened new frontiers in the discovery process for novel therapeutic agents. DNA cloning is a basic tool in genomics and it has been used for over a decade. Drug discovery is currently focused on the identification of gene databases, gene arrays and protein arrays aimed at therapeutic modulation of disease-related genes—which require procedures that may involve cloning techniques. Currently, cloning for pharmacologic products is most applicable in the preclinical area of drug discovery. For example, the identification of specific receptor subtypes occurred via cloning whereas traditional pharmacologic approaches that use agonists and antagonists may have failed to separate binding affinities. Successful therapeutic agents where cloning played vital role resulted in the development of synthetic insulin, growth hormone, erythropoiten and other tissue factors in blood products, Vaccines may be another successful application derived from cloning. Another area where cloning can make a significant impact upon human therapeutics is that this technique may provide a new source of cells for tissue engineering and transplantation. Stem cells, and in particular, embryonic stem cells can differentiate into other cell types such as hepatocytes and neurons to provide normal products for hepatic and neurological diseases. However, the use of cloning embryonic stem cells introduces important ethical, medical and legal issues which require that leaders in government, academic, and religious groups be fully educated in these applications. A close working relationship among these diverse groups is needed to respond wisely to the introduction of new therapeutic opportunities while at the same time providing protection for the individual and the public at large from unethical practises.