Inside the MinION is a little chip with 512 holes in it. Put some DNA into the MinION, and it will pull individual DNA molecules through those pores. DNA molecules carry genetic information in the form of four different chemical bases, like slightly different knots on a piece of string. As a DNA molecule goes through one of the MinION’s pores, the different knots on it are sensed electronically; the signals produced this way are processed inside the MinION and sent through the USB port to your computer, where the string of bases is reassembled as a genome sequence. How long are the pieces of string? The system can read individual strings tens of thousands of bases long—far longer than most sequencing technologies. A MinION should be able to read about a billion bases before its pores run out. That’s a third the length of a human genome. All in a device the size of a matchbox.

There’s no good way of putting a cost on the production of the first human genome sequence in the early 2000s, but the number people tend to quote is $3 billion. The technology in the MinION will apparently do it for well under $3,000. As a byword for head-spinning progress, we’re accustomed to thinking of Moore’s Law, which says (more or less) that the computing power available for a given price doubles every two years. But that gives you only a thousandfold improvement every 20 years. A millionfold in just ten really is something else.

Information in computing “can take two forms: patterns in space that are transmitted across time, termed memory; or patterns in time that are transmitted across space, called code.” Both memories and actions can be represented by a simple string of numbers. Both cells and computers are Turing machines.

The way that the MinION reads the sequence data off single molecules letter by letter as they are ratcheted through its pores is a powerful evocation of Turing’s idea. It is not a Turing machine itself, it can only read, not write. But writing does play a crucial role in the creation of its all-important pores.

The pores are made of proteins inspired by nature but redesigned in computers. Those designs are then written on to DNA molecules. A DNA molecule is a memory, transmitting a pattern of information from one time to another. It is also a code, telling the machinery inside cells the sequence of steps that has to be taken to build a particular protein… And it is also as cool an illustration as you could ask for of the deepest insight to flow from Turing’s work; that both biology and computer technology derive their power from nothing more, or less, miraculous than a string of numbers.