Gene mutations probably play a role in many of today's most common diseases, such as heart disease, diabetes, immune system disorders, and birth defects. These diseases are believed to result from complex interactions between genes and environmental factors. When genes for diseases have been identified, scientists can study how specific environmental factors, such as food, drugs, or pollutants interact with those genes.
Once a gene is located on a chromosome and its DNA sequence worked out, scientists can then determine which protein the gene is responsible for making and find out what it does in the body. This is the first step in understanding the mechanism of a genetic disease and eventually conquering it. One day, it may be possible to treat genetic diseases by correcting errors in the gene itself, replacing its abnormal protein with a normal one, or by switching the faulty gene off.
Finally, Human Genome Project research will help solve one of the greatest mysteries of life: How does one fertilized egg "know" to give rise to so many different specialized cells, such as those making up muscles, brain, heart, eyes, skin, blood, and so on? For a human being or any organism to develop normally, a specific gene or sets of genes must be switched on in the right place in the body at exactly the right moment in development. Information generated by the Human Genome Project will shed light on how this intimate dance of gene activity is choreographed into the wide variety of organs and tissues that make up a human being.
Ethical Issues of the Human Genome Project
Critics express several concerns about the Human Genome Project (HGP), and most involve the extent of the project or its funding. Original proposals for the project emphasized sequencing the entire human genome. This goal, however, is controversial because of the high cost and because many critics believe that sequencing a huge amount of noncoding DNA should have low priority in a time of limited funds for research. On the other hand, most individuals involved in the project agree that detailed genetic and physical maps would be extremely useful. Therefore, mapping of the genome now is the primary goal, with complete sequencing to follow only if the cost becomes reasonable.
Only about 5 percent of the genome contains sequences that are coding regions, and some biologists still maintain there is little point in sequencing the other 95 percent. Because biologists already know that several regulatory signals are in noncoding regions of DNA, a compromise has been reached. A few pilot sequencing projects are focusing on sequencing certain coding regions that are most likely to contain information valuable to the medical and biological communities.
A major criticism of the HGP is similar to that raised against other mega-science projects such as the space station or the superconducting supercollider: The high cost is not justified. This big science vs. little science argument maintains that funding such large-scale projects takes scarce resources from researchers who may study certain areas of particular interest more efficiently. Conversely, others argue that coordination of the HGP is a more efficient way to conduct research in human genetics because it minimizes duplication of effort.
Some critics suggest that the ability to diagnose a genetic disorder before any treatment is available does more harm than good because it creates anxiety and frustration. Indeed, geneticists have isolated several disease-causing gene mutations and have studied them in great detail without developing a treatment. For example, the mutation in the beta-globin gene that results in sickle cell disease was identified in 1956, but there is no treatment as yet. Scientists eventually may develop successful therapies, but until they do, this criticism is significant.
Even in the absence of new treatments, however, the HGP may make diagnosis possible before the onset of symptoms and, thus, make management of the disorder more effective. In addition, improved preconceptual analysis of the parents' genotypes can provide couples with a broader range of options for family planning.
Some critics of the HGP maintain that social and political mechanisms to regulate the ultimate outcomes are insufficient. Because of the genetic variation between individuals, there never will be one definitive human sequence. The lack of a definitive sequence creates uncertainty about the appropriate definition of "normal," which in turn makes the discussion of public policy issues difficult. Questions about controlling the manipulation of human genetic materials concerns these critics, as does the idea that simply because these scientists are able to do this science, they ought to. These critics point to the development of atomic weapons and argue that the science that led to their development caused far more problems than it resolved.
Few religious groups in the United States formally have addressed the specific ethical and public policy issues raised by the HGP, although there is active interdenominational discussion of issues related to human genetics in general. Public policy debates are enriched considerably by input from these various groups.
