Covering the bases: Quantum effect may hold promise for low-cost DNA sequencing, sensor ap...( A ghostly property of matter called ...)

A ghostly property of matter, called quantum tunneling, may aid the quest for accurate, low-cost genomic sequencing, according to a new paper in Nature Nanotechnology Letters by Stuart Lindsay and his collaborators at the Biodesign Institute of Arizona State University. Tunneling implies that a particle, say an electron, can cross a barrier, when, according to classical physics, it does not have enough energy to do so.

Unraveling the DNA sequences of the human genome a decade ago was a remarkable achievement. Today, the task of sequencing some 3 billion chemical base pairs of the genomeenough information to fill a 20-volume encyclopediaremains a daunting challenge, thus far accomplished largely through brute force means. Such methods are typically slow and extravagantly expensive, (though costs have dropped considerably from the initial sequencing of the human genome, which took 11 years at a cost of $1 billion.)

Bringing the power of DNA sequencing to every individual will require new, affordable technologies to help mine the wealth of information DNA can provide concerning morphology, hereditary traits and predisposition to disease.

Various techniques for sequencing DNA have been used to determine the identities of the four nucleotide basesadenine, thymine, cytosine and guaninewhich make up the ladder rungs of the DNA's double helical structure. Most of these require snipping DNA into hundreds of thousands of short fragments, unzipping the helix and reading a few hundred to a few thousand bases at a time. Finally, all of the information from the DNA pieces is reassembled into a picture of the complete genome, with the help of massive computing power.

ASU Regents' Professor and Carson Presidential Chair of Physics and Chemistry, Stuart Lindsay, who also directs the Biodesign Institute's Center for Single Molecule Biophysics, summarizes one of the chief physical obstacles to more efficient identification of DNA
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