Begun in 1990, the sequencing of the human genome was a daunting task that took some 13 years to complete. Large-scale DNA-sequencing projects are now more commonplace, so scientists are investigating new approaches in order to save time and money. A report published online by the journal Nature describes one such method that is 100 times faster than conventional ones.
The novel sequencing technique, designed by Jonathan M. Rothberg of 454 Life Sciences Corp. in Branford, Conn., and his colleagues, uses tiny fiber-optic reaction vessels that measure just 55 micrometers deep and 50 micrometers across--a slide containing 1.6 million wells takes up just 60 square millimeters. The set up allows for the amplification and sequencing of hundreds of thousands of DNA molecules simultaneously. Using light to measure the reactions, tests of the apparatus indicate that it can sequence 25 million bases in a single four-hour run with greater than 99 percent accuracy.
To compare the approach to standard procedures, one member of the research team successfully sequenced and assembled the entire genome of the parasitic bacterium Mycoplasma genitalium, which includes 580,069 base pairs, in a single run on the new machine. The results cover 96 percent of the genome with 99.96 percent accuracy. The authors conclude that the continued miniaturization of fiber optics suggests that in the future, this technique could become even faster when more sequencing wells can fit in a given area.