The HeliScope is the first commercial machine to sequence a single piece of DNA rather than one copied many times. Each “flow cell” (above) has 25 channels, each capable of holding 16 million strands of DNA for sequencing. A coating on the surface of the cell allows it to be washed clean between reactions. Credit: Porter Gifford

In the corner of Helicos BioSciences' ­offices in Cambridge, MA, a screen on the face of what looks like a giant refrigera­tor flashes a countdown: 10 days, five hours, and 51 minutes until it finishes reading the sequence of all the DNA that has been fed into it. The high-­throughput machine, a complex configuration of tubes, lasers, and chemi­cals, contains two plates, each with 25 ­microfluidic channels etched into it. Each channel is capable of holding and sequencing a separate DNA sample. Sequencing the samples in parallel, the machine takes just one hour to read 1.3 billion of the chemical "bases"--known as A, C, T, and G--that make up a strand of DNA.

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