Starting next spring, a complete human-genome sequence can be ordered for $5,000 through a new service announced by Mountain View, California startup Complete Genomics. This stunning price drop (sequencing currently costs about 20 times that amount) could completely change the way that human genomics research is done, and open up new possibilities in personalized medicine.
A $5,000 genome would enable new studies to identify rare genetic variants linked to common diseases, and could open up the sequencing market to diagnostic and pharmaceutical companies. It could make genome sequencing a routine part of clinical drug testing. Complete Genomics anticipates the capacity to sequence 1,000 genomes in 2009 and 20,000 in 2010. That would represent a massive jump; only a handful of human genomes have been sequenced to date.
Complete Genomics says that its cheap price tag comes thanks to two innovations: a way to densely pack DNA and a method to randomly read DNA letters. First, an 80-base-pair piece of DNA is inserted into a circular piece of synthetic DNA and replicated 1,000 times with a specialized enzyme. That large aggregate of DNA compresses into a tightly packed ball, and these DNA “nanoballs” are then packed onto specially fabricated arrays. The high density of DNA allows large volumes to be sequenced quickly with few reagents, one of the most costly components of the process.
p>Next, Complete Genomics determines the sequence of the target DNA using a series of fluorescently labeled DNA strands designed to bind to corresponding letters. But while sequencing technologies currently in use read the sequence sequentially, letter by letter, Complete Genomics’ labels bind to the target DNA randomly. But the labels are designed to allow scientists to deduce the position of each highlighted base, which allows a computer to reconstruct the sequence of the target DNA.