A British company's new technique for reading DNA could move medicine a step closer to an affordable gene scan for every patient.

Oxford Nanopore Technologies announced this week that it had successfully tested a system that can read DNA directly. That approach cuts out the expensive equipment, chemicals and lab time needed for current scanning methods, said Dr. Gordon Sanghera, Oxford's chief executive.

"You move from days to hours to get the same information, and the equipment required is a lot simpler," Sanghera said.

Many current scanners use fluorescent chemical tags that attach to each of the four chemicals that make up a "letter" in the DNA sequence. Sophisticated cameras and software read the tags to identify the genes.

The system described by Oxford in the current issue of Nature Nanotechnology sends DNA one letter at a time through a microscopic, biologically engineered hole, or "nanopore."

An electrical current passed across the hole responds differently to each of the four letters in the genetic code, allowing scientists to accurately read each letter.

"This demonstration that you can distinguish among the four bases with a purely electronic signal I think is just an incredible advance," said Jeffrey Schloss, director of the National Human Genome Research Institute's sequencing technology program.

Backers of so-called personalized medicine say whole-genome scans will let doctors make better diagnoses, prescribe gene-specific treatments and predict health risks.

First the cost still needs to come way down.

Advances in sequencing technology have been swift since The Human Genome Project completed its map of the genetic code in 2003 for $300 million. The current rate hovers around $100,000, though the federal government is pledging millions to DNA sequencing research in hopes of achieving a $1,000 genome scan by 2014.

Oxford believes its nanopore sequencing could be a contender for the $1,000 scan. However, the company has used nanopores to read only individual DNA letters so far. The company is still working to improve its system to scan entire strands of DNA.

On the Net:

Oxford Nanopore: http://www.nanoporetech.com

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