Since the discovery in 1953 by Watson and Crick of the structure of DNA and the subsequent revolution in molecular biology and genetic engineering which occurred as a result of this discovery, the science of biotechnology has been revolutionised.
One of the earliest examples of this new technology was the production of recombinant human insulin by inserting the human insulin coding gene into a bacterial system, growing the recombinant bacterial cells in liquid culture and extracting the insulin protein. This has the advantage that human insulin can be used for the treatment of diabetes, instead of bovine insulin which was used previously and which caused some adverse cross reactions.
Another example in medicine is the production of recombinant human growth hormone in bacterial systems – previously, growth hormone was extracted from human pituitaries and used to treat dwarfism – this had the major disadvantage that disease causing agents such as those responsible for CJ disease and HIV were carried over, resulting in disease in the treated individuals. Recombinant HGH overcomes these problems and moreover, can be produced in unlimited quantities. More recently, the realisation by Sir Alec Jeffreys that hyper-variable regions of the human genome could be used to identify individuals in a population has led to the new technology of forensic DNA fingerprinting which is now extensively used in criminal investigations.
The identification of disease linked genetic markers has also led to the development of genetic tests for many human genetic diseases – in some cases, techniques to alleviate these diseases by introducing normal copies of the mutated gene into somatic cells has been tried.
In Agriculture, recombinant DNA technology has had an enormous impact. This has depended largely on the development of transformation systems for various plant species - millions of acres worldwide have now been planted with genetically engineered food and non – food crops (cotton , maize, soya bean, rice, tomato etc) which incorporate traits for disease resistance, pest resistance, herbicide tolerance, improved vitamin content, increased amounts of antioxidants etc. A variety of rice “Golden rice” has been produced which has increased vitamin A content and which helps to alleviate vitamin A deficiency which can lead to blindness in young children. Tomatoes with increased lycopene content have also been engineered – these have the ability to reduce the concentration of damaging free radicals in the human body. Transgenic crops resistant to diseases and pests reduce the need for artificial pesticides and biocides and are thus more environmentally friendly, as well as reducing the input into the crop. The increasing human population as well as changes in global climate necessitates the development of new varieties of crops better able to resist these changes. More recently, potato plants have been engineered to synthesise vaccines for human therapy.
Molecular biology and biotechnology is also having an increasing impact in many other areas of biology including bioremediation, environmental clean up, animal husbandry and aquaculture. An increasing number of organisms are being engineered to break down and detoxify pollutants, indeed, in 1980, Pseudomonas bacteria were genetically engineered to breakdown oil spills. In commercial fisheries, salmon have been engineered to express growth hormone – as a result, these transgenic fish grow faster than wild-type fish, and can therefore come to market faster. Cattle and sheep have been engineered to express valuable pharmaceuticals in their milk and could be engineered to have a greater muscle to fat ratio. As can be seen from the examples above, molecular biology and biotechnology will continue to have an increasing impact on human society.
According to science-engineering