The UK firm Oxford Nanopore built the device, called MinION, and claims it can sequence simple genomes – like those of some viruses and bacteria – in a matter of seconds.
More complex genomes would take longer, but MinION could also be useful for obtaining quick results in sequencing DNA from cells in a biopsy to look for cancer, for example, or to determine the genetic identity of bone fragments at an archaeological dig.
The company demonstrated today at the Advances in Genome Biology and Technology (AGBT) conference in Marco Island, Florida, that MinION has sequenced a simple virus called Phi X, which contains 5000 genetic base pairs.
Proof of principle
This is merely a proof of principle – "Phi X was the first DNA genome to be sequenced ever," says Nick Loman, a bioinformatician at the Pallen research group at the University of Birmingham, UK, and author of the blog Pathogens: Genes and Genomes.
But it shows for the first time that this technology works, he says. "If you can sequence this genome you should be able to sequence larger genomes."
Oxford Nanopore is also building a larger device, GridION, for lab use. Both GridION and MinION operate using the same technology: DNA is added to a solution containing enzymes that bind to the end of each strand.
When a current is applied across the solution these enzymes and DNA are drawn to hundreds of wells in a membrane at the bottom of the solution, each just 10 micrometres in diameter.
Within each well is a modified version of the protein alpha hemolysin (AHL), which has a hollow tube just 10 nanometres wide at its core.
As the DNA is drawn to the pore the enzyme attaches itself to the AHL and begins to unzip the DNA, threading one strand of the double helix through the pore.
The unique electrical characteristics of each base disrupt the current flowing through each pore, enough to determine which of the four bases is passing through it. Each disruption is read by the device, like a tickertape reader.
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