The current method of mapping the human genome depends on the same kind of signpost or marker that is used in the forensic technique of DNA fingerprinting. But these markers, which consist of repetitive bits of DNA repeated a varying number of times in different individuals, are technically difficult to work with. So far, there has been very little success in digging out the genetic roots of multi-gene diseases. Hence, considerable interest was aroused by a recent calculation that multi-gene diseases could be cracked through the snip approach. Citing the Risch-Merikangas paper, Dr. Francis S. Collins, director of the human genome project at the National Institutes of Health, persuaded the directors of other N.I.H. divisions to join in financing a grand hunt for snips, based on the premise that genetic factors contribute to almost every human disease.
Snips are also the basis of a fashionable new approach to drug design known as pharmacogenomics.
The premise is that people respond differently to drugs based on their genetic makeup. With the use of snips, it should be possible to tailor drugs to patients, selecting the drug that works best for a person and excluding from drug trials the people likely to suffer side effects. If the approach works, drug companies might end up selling fewer drugs, but could charge more for the tailored approach. Once the snips are identified, they can be used for many purposes. A particularly striking application is that of the snip chip.