Scientists Hunt SNPs to Uncover Variation, Disease
Why does one man live to celebrate his hundredth birthday with a glass of wine in one hand and a cigar in the other while another succumbs in midlife to cancer or heart disease? And why may one woman's breast cancer be effectively eradicated while another's shows no significant response to the same treatment?
The explanations may reside in the cumulative effect of a small number of differences in DNA base sequence called single-nucleotide polymorphisms (SNPs), which underlie individual responses to environment, disease, and medical treatments. SNPs are the most common type of sequence variation. Other variations include the number of base insertions and deletions and sequence repeats (called mini- and microsatellites). Some disease-causing mutations are SNPs, for example, the single base change in the gene associated with sickle cell anemia. SNPs occur inside and outside genes, about once every 100 to 300 bases throughout the human genome.
DNA variations are important in understanding the genetic basis for disease and individual responses to environmental factors, as well as for such normal variations in biological processes as development and aging. For this reason, scientists in the public and private sectors are beginning to focus their attention on methodically searching for SNPs throughout the human genome. [See articles on new HGP goals and private human genome sequencing projects.]
In 1997 the NIH National Cancer Institute launched a Genetic Annotation Initiative to gather SNPs in regions of thousands of cancer-associated genes. In another NIH program, a 1998 RFA involves 18 institutes interested in developing genomic-scale technologies or in implementing projects to catalogue and detect SNPs in different DNA samples.
SNPs generated in these public projects will be freely available from dbSNP, a new database at the NIH National Center for Biotechnology Information, which serves as a central repository for SNPs and for short-deletion and insertion polymorphisms. [Denise Casey, HGMIS,caseydk@ornl.gov]
The electronic form of the newsletter may be cited in the following style:
Human Genome Program, U.S. Department of Energy, Human Genome News (v10n1-2).
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