
True Single Molecule Sequencing approach to genomic analysis directly measures single DNA molecules, without amplification. The technology accurately interrogates billions of single strands of DNA (or RNA) in parallel by detecting single nucleotide incorporations on each of the single strands. Original DNA samples are first fragmented and the DNA double-helix is melted into single strands. Billions of DNA molecules are captured on a proprietary surface within a flow cell and serve as templates for the sequencing-by-synthesis process. Fluorescently-labeled nucleotides – C, G, A or T – are added one at a time and incorporated into the growing complementary strand by a DNA polymerase enzyme. Unused nucleotides are washed away. Upon illumination with a laser, the incorporated nucleotides emit light that is detected by the HeliScope Single Molecule Sequencer. The sequencer captures images to record which strands incorporated which nucleotides. The fluorescent label is removed before the next nucleotide is added to continue the cycle. Tracking nucleotide incorporation on each strand determines the exact sequence of each individual DNA molecule. The Helicos Genetic Analysis Platform consists of: the HeliScope Single Molecule Sequencer, the HeliScope Sample Loader and the HeliScope Analysis Engine – as well as reagents, flow cells and software. Helicos BioSciences Corp., 877-243-5426, www.helicosbio.com.