DNA sequencing is becoming both faster and cheaper. Now, it is also becoming tinier.

A British company said on Friday that by the end of the year it would begin selling a disposable gene sequencing device that is the size of a USB memory stick and plugs into a laptop computer to deliver its results.

The device, expected to cost less than $900, could allow small sequencing jobs to be done by researchers who cannot afford the $50,000 to $750,000 needed to buy a sequencing machine. null