The ability to sequence the genome of a virus in the field is
invaluable, allowing the source of the infection to be tracked and
providing epidemiologists an important weapon in stopping the spread of
disease. Until now, however, DNA sequencers have been large, fragile,
and extremely slow to deliver results. Not exactly the sort of equipment designed to be schlepped around We The MinION: a game-changer in the realm of DNA sequencing, biochemists are thrilled with this new handheld technology. Image from www.nanoporetech.com.st Africa in the midst of an epidemic. A UK company, Oxford Nanopore
Technologies, has changed all that with the release of the MinION — a
handheld DNA sequencer that can be plugged into a laptop to deliver
results as they are available.
The technology, which bioinformatician Joshua Quick calls the "democratization of sequencing" is the first to take advantage of the nanopore method of DNA characterization. In this strategy, strands of DNA are fed through a nanoscale hole in a substrate that is monitored electrically. Different base pairs of the DNA strand produce detectable changes in conductivity. The company first released the device in the spring of last year on a trial basis — researchers needed only to pay a US$1000 deposit to begin testing the MinION — and this year the results are being discussed.
Nanopore sensing: electrical changes are detected as the DNA double helix passes through a tiny hole in a conductive material. Image from www.nanoporetech.com.
Overall, researchers have been thrilled by the portable sequencers with reported applications ranging from tracking Ebola in Guinea to elucidating frog genomes in Tanzania to a planned trip to the International Space Station. The relatively low cost of the device, which will of course drop further in future iterations, has even led to proposals like putting it in the hands of ‘citizen scientists’ to map biodiversity in Maine’s Acadia National Park; a plan that would have been completely infeasible with traditional sequencing technology.
As the MinION is more widely adopted among biologists, computer scientists are jumping on board to develop improved operating software. Error-correcting software, in particular, is proving valuable as the handheld device has so far produced a greater number of sequencing errors – 5 to 30% – as compared with more large-scale traditional technology. Researchers are also working on a mobile app which could allow for in situ identification of unknown species using just the MinION and an iPhone.
Traditional large DNA sequencer: technology like this has its place, but is not useful for field studies or off-planet investigations.
Given that DNA sequencing was only developed in the late 1970s and involved enough equipment to fill a small room, it is remarkable how quickly we have advanced in such a short time. The MinION’s small size and affordability represents a valuable step forward by not only providing scientists with a new tool, but also by bringing DNA sequencing a step closer to availability to average consumers who will certainly come up with novel and innovative uses for the product. Additionally, the company is now in the process of developing a high-speed sequencer that will elucidate the human genome in just 15 minutes.
