New Chip off the Old Block; September 1996; Scientific American Magazine; by Gibbs; 2 Page(s)

In 1971 a small company in Santa Clara, Calif., perfected a way to shrink 2,300 transistors onto a single integrated circuit and began selling the first microcomputer chips. Through mass production, Intel made microprocessors affordable, launching the personal- computer industry and a multibillion- dollar business. Now, 25 years later, a small start-up just a few miles from Intel headquarters has adapted the same production methods to fabricate microchips that process DNA rather than electrons. Affymetrix claims its GeneChip systems can boost the field of genetic medicine the same way desktop computers helped business: by gathering information much more quickly and cheaply than previously possible.

Held in the hand, a GeneChip looks unremarkable. A simple plastic case small enough to conceal in one¿s palm holds a glass slide the size of a small postage stamp, on the inside of which is a dull, dark coating. But given a drop of blood and a few hours, a GeneChip system can reveal not only whether a subject has HIV but also whether the particular strain of the AIDS-causing virus in his or her body carries mutations that make it resistant to certain drugs. With a different chip (each costs only a few dollars to mass-produce), the same system can screen for any of the 450 or so mutations linked to cystic fibrosis. In contrast, standard genetic testing would take 12 hours to screen an HIV sample and perhaps a week to search for all the genetic risk factors for cystic fibrosis.