THERE is a new entrant in the race to speed up DNA sequencing.
Modern sequencing machines rely on the decades-old Sanger method. While automation and refinements have dramatically increased its speed and cut the price, the scope for more improvements is limited.
The latest rival, developed by Jungyue Ju’s team at Columbia University in New York city, involves reading off the sequence as nucleotides are added to a single strand to rebuild a double strand. The key is ensuring that only one nucleotide is added at a time.
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So far they have only sequenced DNA 12 base pairs long, working with thousands of identical copies because their equipment cannot detect fluorescence from a single molecule. With refinements it should be possible to sequence single strands, of much greater length. What’s more, millions of different strands could be simultaneously sequenced on the same chip (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0501965102).
“This paper represents an exciting, impressive proof of principle, one important early step on the long path to cheap genome sequencing,” says Chad Nusbaum, a geneticist at MIT.
