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Since Helicos BioSciences Corp. launched its single-molecule sequencing platform in 2008, companies have been competing to improve the DNA sequencing technique's sensitivity, speed, read length and price. Life Technologies Corp. and Pacific Biosciences Inc. say they have achieved these goals by optimizing detection and reagent use. Pacific is already shipping its machines to early customers, and Life Technologies will make its first shipments by year end.

In single-molecule sequencing, also known as sequencing by synthesis, a DNA polymerase incorporates fluorescently labeled nucleotides along an individual, unamplified DNA template. Each of the four possible nucleotides carries a different fluorescent dye. The fluorescent emission pattern generated during this iterative process, in which the incorporated nucleotides are identified by the color of the emitted light, corresponds to the template's nucleotide sequence...