One early method, known as capillary electrophoresis, uses electric current to attract DNA molecules to a "detection window." Laser light activates fluorescent tags in the DNA fragments as they pass the window. The fragments produce a color readout that is translated into a genetic sequence.
While reliable and accurate, the technique has been "traditionally been expensive and slow," Church said.
But as computers become smaller and more powerful, they are pushing down the cost of genetic sequencing. Instead of detection windows, the latest devices now use digital cameras to capture split-second images of DNA.
More efficient DNA sequencing techniques are also helping to lower costs and speed up the process.
Many labs and scientists have invented entirely new methods to read the human genome. One company, 454 Life Sciences, has found a way to map more DNA at one sitting by reading sequences in parallel, rather than one by one.
Chris McLeod, CEO of the Connecticut start-up, said, "With capillary electrophoresis you can read only 384 molecules simultaneously. With our process you can read 200,000."
454's strategy relies on increasing the density of DNA read at a time. McLeod hopes to increase the rate even more and says the method could eventually reduce the cost of genome sequencing to about a hundred thousand dollars.
The first step toward affordable genome maps appears within reach. But hitting the thousand-dollar benchmark envisioned by the National Human Genome Research Institute appears more theoretical than practical for now.
Jeff Schloss directs technology development at the institute. He says further equipment miniaturization is key. So is eliminating the need to duplicate and separate strands of DNA.
One possible solution, he says, employs nanotechnologythe art of manipulating materials at the molecular level.
"With this approach, long strands of DNA are threaded through a small pore. Sensors would read the DNA as it is pulled through," Schloss said.
The "nanopore" approach could potentially read an entire human genome in just a few hours, although scientists still do not fully understand the physics of the proposed process.
Affordable genome sequencing offers many potential benefits. With an individual's genetic data on hand, doctors could create personalized treatments for patients and recommend changes in diet and other behaviors.
The volume of human genetic data would also likely boost the medical community's understanding of diseases and genetic disorders.
But some experts say privacy and ethical issues could overshadow the scientific advances of affordable DNA mapping.
Jean McEwen is program director for genetic variation, law, and social policy at the National Institutes of Health. She says insurance companies or employers might discriminate against individuals based on their genetic information.
"One of the things we worry about is the tendency to overinterpret [genetic] information," McEwen said. She notes that many factors outside of genes, such as a person's environment and lifestyle, can also cause disease.
In the U.S. nearly every state has already enacted genetic nondiscrimination laws. And last year the U.S. Senate passed the Genetic Information Nondiscrimination Act of 2005 to ensure comprehensive protection for all Americans. The bill has yet to move through the House of Representatives.
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