Science doi:10.1126/science.1181498 (2009)

A team has sequenced three human genomes for US$4,400 each — at least ten times less than that achieved with other technologies.

Radoje Drmanac and Dennis Ballinger of Complete Genomics in Mountain View, California, and their collaborators developed a technique that chops DNA into fragments, makes many copies of these, rolls them up into 'nanoballs' and binds them to patterned silicon arrays. Nine-base-long probes of specific sequences — tagged with one of four different dyes, each corresponding to a 'letter' of the DNA code — are then added and bind to complementary DNA sequences with the help of synthetic 'adaptors'. Fluorescence imaging picks up the signal from the bound probes.

The technique keeps reagent use, and thus sequencing costs, low. It identified 94–98% of genetic variants when compared with established methods.