How the Heliscope Sequences DNA
Helicos Biosciences’ novel machine could speed up sequencing and unearth new disease-linked genetic variations.
-
1
The HeliScope is the first commercial machine to sequence a single piece of DNA rather than one copied many times.
-
2
Each “flow cell” 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.
-
3
To start the sequencing process, a scientist uses a multitip pipette to inject DNA samples into the flow cell.
-
4
The flow cell is then loaded into the HeliScope, which contains a complex optical system and four digital cameras. A granite slab, seen as a horizontal stripe across the top of the photo, prevents the instrument from vibrating.
-
5
DNA bases–A, C, T, and G–and DNA polymerase, the enzyme that catalyzes the sequencing reaction, are fed to the flow cell through a complex fluidics system at precisely timed intervals.
-
6
A low-power laser illuminates the sequencing reactions, which are recorded by the digital cameras.
-
7
The data recorded by the cameras is transferred to an accompanying processing center, which converts the images into strings of DNA letters. A specialized algorithm assembles the overlapping fragments into a longer sequence of DNA.
0 comments. Share your thoughts » 0 comments about this story. Start the discussion »