How It Works | Automated DNA Sequencer

Sequencers have come a long way since 1986.

The Scientist Staff
Aug 28, 2005
<p>Automated DNA Sequencer</p>

Andrew Meehan

Sequencers have come a long way since 1986. Back then, Applied Biosystems' first automated DNA sequencer, the 370A, scanned bands coming off the bottom of a slab gel. Yet it was barely automated: Technicians loaded and poured the gels by hand, and ran the reactions manually, too. With 16 lanes, a good gel would yield 300 bases per sample per 12-hour run; a production lab could thus generate 9,600 or so bases per day.

Today, Applied Biosystems' flagship 3730xl sequencer (shown here) is a capillary electrophoresis-based affair. Each capillary is the equivalent of one slab gel lane, and the 3730xl can run 96 of them in parallel, generating some 900 bases each. No more manual sample loading; the machine simply dunks the capillary array into a sample plate and off it goes. Add automation on the front end to run the sequencing reactions and prepare...