DNA Chips Accelerate Genetics Research

 

Scientists have recently learned how to pack thousands of snippets of DNA onto silicon chips. Until now, a study of one gene could take 7-10 days. With a DNA chip, the same study can be done on 6,400 genes in an afternoon.

Several techniques are used, but all rely on the double-stranded nature of DNA. Single strands of known DNA sequences are synthesized on a chip. The unknown sequences in a sample are tagged with phosphorescent molecules. When the sample is poured onto the chip, the strands bind to complementary or near-complementary sequences on the chip. When a laser is shined on the chip, the areas with the best matches glow brightest. A computer analyzes the pattern of light to infer the sequences in the sample.

In a few years, DNA chips, also called gene arrays, may become powerful tools for analyzing environmental problems. For example, one small array could contain the genetic blueprints of some 10,000 microbes that live in soils, lake water, or drinking water. A computer would compare the genes on the chip to those in the soil or water, testing for all 10,000 microorganisms at once.

DNA chips will also help scientists peer into the genes of mammals, fish, and birds to see how toxic chemicals tamper with their genetic codes, according to Warren Heideman and Richard Peterson, professors in the School of Pharmacy at UW-Madison. With support from UW Sea Grant, Heideman and Peterson are examining the effects of dioxin-related chemicals on the development of zebrafish.

"Up until now, we’ve had to look at one gene at a time. Here we can look at sort of an orchestra of how these all of these genes play out during development," Peterson said.

Environmental applications are a few years away, but the new technology is already used to identify mutations of the HIV virus that resist drug treatments. It will also be used one day to identify people whose genetic makeup places them at high risk for everything from Alzheimer’s and breast cancer to minor viral infections.

--John Karl

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This page created 24 February 1999
Last updated 26 February 1999 Karl
All contents copyright 1999 University of Wisconsin Sea Grant Institute

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