What will SNPs bring us?

Although more than 99% of human DNA sequences are the same across the population, variations in DNA sequence can have a major impact on how humans respond to disease; environmental insults such as bacteria, viruses, toxins, and chemicals; and drugs and other therapies. This makes SNPs of great value for biomedical research and for developing pharmaceutical products or medical diagnostics. SNPs are also evolutionarily stable --not changing much from generation to generation --making them easier to follow in population studies.

Scientists believe SNP maps will help them identify the multiple genes associated with such complex diseases as cancer, diabetes, vascular disease, and some forms of mental illness. These associations are difficult to establish with conventional gene-hunting methods because a single altered gene may make only a small contribution to the disease.

Several groups are working to find SNPs and ultimately create SNP maps of the human genome. Among these groups are the U.S. Human Genome Project and a large group of pharmaceutical companies called the SNP Consortium. The likelihood of duplication among the groups is small because of the estimated 3 million SNPs, and the potential payoff is high.

In addition to the pharmacogenomic, diagnostic, and biomedical research implications, SNP maps are expected to identify thousands of additional markers along the genome, thus simplifying navigation of the much larger genome map being generated by researchers in the Human Genome Project (HGP).