Recombinant DNA, also written as rDNA, is the combining of genes from two or more organisms. The procedure is to construct a DNA molecule in vitro and then insert it into a host cell or organism. The product of the procedure usually is defined as being genetically engineered, although the two terms genetically modified or transgenic are also used. Recombinant DNA is one of three types of cloning and often is mistakenly identified with one of the other two types: reproductive cloning and therapeutic cloning, although there is overlap.
Reproductive cloning (cloning is from the Greek word for twig) has been used for plants since ancient times, as a twig from a plant would be put in the ground and grow. But the first cloned animal, a tadpole, did not occur until 1952. Much popular attention has been given to reproductive cloning, largely since the cloning of a sheep, “Dolly,” in 1997, by the Roslin Institute in Scotland. Since then, a number of other animals have been cloned (e.g., mice, cows, pigs); attempts to clone some other animals (e.g., monkeys, cats, dogs) have been unsuccessful; and the possible cloning of humans has become a major topic of concern, with much opposition. Mice are the main source of animal-cloning experiments, but cloning of pigs is a goal because their tissues and organs are similar to those of humans. Reproductive cloning is very expensive, and most experiments are not a success.
The most popularly known example of therapeutic cloning is stem cell research, which first became a controversial political issue in the United States during the 2004 presidential election, when President George W. Bush opposed the furtherance of the small amount of stem cell research the United States has sponsored and his Democratic challenger, John Kerry, supported an increase in stem cell research. Because an embryo is destroyed in the process, some people object to stem cell research on religious grounds, as being similar to abortion. Possibilities are cures for cancer, heart disease, Alzheimer’s, and other serious medical conditions. In the same 2004 election, California voted to provide $3 billion over 10 years for stem cell research, 12 times as much annually as the nation’s 2004 funding. The hope is that in the future, entire organs can be produced from single cells and be used to replace defective organs.
Recombinant DNA has not received the controversial emotional and political coverage received by animal cloning and stem cell research. However, it does exert an important role in the success of biotechnology and has led to many successful advances. Crucial vaccines are in the pipeline. Foods, for example, have been produced that can resist insecticides, pesticides, or viruses, provide more nutritional value, grow faster and larger, or resist bad weather conditions.
The 1953 discovery, by James Watson and Francis Crick, of the structure of DNA started the continuing explosion of genetic research, including recombinant DNA technology. In 1962, Watson, Crick, and Maurice Wilkins received the Nobel Prize for Physiology and Medicine. Rosalind Franklin, the fourth discoverer, had died in 1958 at age 37. Among other examples of the explosion, the genetic code was cracked in 1966. In 1972, Paul Berg pasted two DNA strands together, forming the first recombinant DNA molecule; and the following year, Stanley Cohen, Annie Chang, and Herbert Boyer produced the first recombinant DNA organism by splicing a recombinant DNA molecule into bacteria DNA. In 1975, at Asilomar, California, an international conference of scientists asked the government to regulate recombinant DNA experiments, and in 1976, many types of experiments were restricted. The recombinant DNA Advisory Committee was established by the U.S. National Institutes of Health. The same year, two famous scientists founded Genentech, Inc., a biotechnology company whose goal was to develop and market recombinant-DNA-based products.
The controversy over whether private businesses should be able to patent new knowledge would be bitter and long-lasting, but a very expensive and competitive entrepreneurial race had begun, largely by medical, pharmaceutical, and agricultural concerns. In 1977, the U.S. Congress failed at attempts to pass more regulations, and in 1980, the United States allowed Exxon to patent an oil-eating microorganism. In 1988, the first patent was awarded for a genetically altered animal, a mouse highly susceptible to breast cancer. In 1989, the National Center for Human Genome Research, with James Watson as head, was created to oversee the Human Genome Project’s goal to map and sequence all human DNA by 2005. The center was formally begun in 1990, and that year, anthropologists and the public also saw the book, Jurassic Park, which increased public interest and concern through a story of bioengineered dinosaurs running amuck, with dangerous results. The book became a popular movie in 1993.
How will recombinant DNA affect the future? The possibilities are great for medical advances, for helping fight starvation, for improving the environment, and for other areas. There are numerous biotechnology companies, with many successful and unsuccessful research projects. But there are and will continue to be serious ethical controversies. A major amount of opposition will come from people who because of their religious beliefs view recombinant DNA technology as changing their supreme being’s definition of life. A cultural lag between knowledge and allowable application of that knowledge will continue to exist in many areas. There also is a fear that unknown and very negative results might arise from combining different life forms.
Other concerns are over the treatment of animals, the tremendous knowledge and financial benefits that might go to a selected few individuals or governments, the probability that poorer countries might have their natural resources exploited but receive no benefits, the confusion that people will experience because of the complexities of new products and results, and the possibilities of unexpected negative medical reactions.
Despite concerns, biotechnology has been safe; recombinant DNA has more precise methods than traditional biotechnology; and oversight has become more flexible. The Human Genome Project was completed in 2003, ahead of schedule, and will continue to provide much more helpful genetic information far into the future.
References:
- Cranor, C. F. (Ed.). (1994). Are genes us? The social consequences of the new genetics. New Brunswick, NJ: Rutgers University Press.
- Relethford, J. H. (2001). Genetics and the search for modern human origins. New York: Wiley-Liss.
- Watson, J. D. (with A. Berry). (2003). DNA: The secret of life. New York: Knopf.
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