At present however, sequencing technology remains cumbersome and cost prohibitive for most clinical applications, though this may be changing, thanks to a range of innovative new techniques.
In the current issue of Science, Stuart Lindsay, director of Arizona State University's Center for Single Molecule Biophysics at the Biodesign Institute, along with his colleagues, demonstrates the potential of one such method in which a single-stranded ribbon of DNA is threaded through a carbon nanotube, producing voltage spikes that provide information about the passage of DNA bases as they pass through the tube-a process known as translocation.
Carbon nanotubes are versatile, cylindrical structures used in nanotechnology, electronics, optics and other fields of materials science. They are composed of carbon allotropes-varied arrangements of carbon atoms, exhibiting unique properties of strength and electrical conductivity.
Traditional methods for reading the genetic script, made up of four nucleotide bases, adenine, thymine, cytosine and guanine (labeled A,T,C,&G), typically rely on shredding the DNA molecule into hundreds of thousands of pieces, reading these abbreviated sections and finally, reconstructing the full genetic sequence with the aid of massive computing power.
A decade ago, the first human genome-a sequence of over 3 billion chemical base pairs-was successfully decoded, in a biological tour de force. The undertaking required around 11 years of painstaking effort at a cost of $1 billion dollars. In addition to the laboriousness of existing techniques, accuracy is compromised, with errors accumulating in proportion to the number of fragments to be read.