In recent scientific news, researchers at the Welcome Trust Genetics institute, in collaboration with scientists from California have pioneered a new method of storing computer information using DNA.
At first this sounds fairly crazy, akin to using your red blood cells to watch movies, or your nerve cells to download games. However, computer storage and DNA aren’t such different systems. For example, both use a small number of repeated units to store data. In computers, information is stored in bits: a long series of 1’s and 0’s. This is done in DNA too, with the four bases A, T, C, and G taking the place of bits. Both massive strings of data are decoded by a hugely complex system, to turn them into useful functions. For bits, we use computers. For DNA, nature uses you.
DNA may even hold some advantages over bits for computer storage. For starters, DNA contains four repeating units, compared to only two kinds of bits. This means that the same information can be stored using fewer units in DNA.
Because it has four units compared to two in bits, and because of the way it is stored, DNA data can also have built in redundancy. This means that if data is damaged, it can usually be recovered. As Watson and Crick first showed in the 50’s, DNA is a double helix. This means there are two strings of bases, running parallel. These two strings are complementary, which means that if you know the base in one strand, you will always know the base in the other. For example, an A in one strand means that the other strand will always contain a T directly opposite. Because four bases are involved, you can store information on DNA without ever repeating the same base twice. This, combined with DNA’s double strand, means that if any bases are damaged, you can immediately work out what they were, and repair them, restoring any lost data.
DNA also packs in information incredibly densely. Each and every one of your cells contains about 6 picograms (a thousandth of a millionth of a gram) of DNA. Stored in this absolutely tiny amount of DNA is the computer equivalent of around 3.3GB of data, that data being your genes, which is about enough space for a movie-length HD video file. There are about 1014 (10,000 billion billion) cells in the average human body, totalling about one pound of DNA. At this rate, all the DNA in two human bodies would be about enough to store all the information used on the internet for a month. Most similarly weighted hard drives manage a few measly terabytes.
Despite all these amazing properties, it’s taken quite a while to create a feasible working model, which is why these latest findings have created a fair amount of excitement. The project mentioned at the start of this article has managed to encode 578kB worth of files, including text files of all of Shakespeare’s sonnets, and Dr Martin Luther King’s ‘I Have a Dream’ speech, synthesise the required DNA, and read the files back with 100% accuracy. They even cleverly set their data storage sequences so that it can be read in both directions!
However, the sheer cost of the process means that you shouldn’t be expecting to store any essays on your DNA hard drive any time soon. DNA synthesis and sequencing, whilst well established, costs tens of thousands of pounds, as well as needing highly specific machinery. For DNA storage to be commercially viable, it would need to cost less than 1% of what it currently does to produce, which is a long way to go.
All hope is not lost, though. The fields of DNA synthesis and sequencing are advancing extremely quickly, in both efficiency and cost. For example, the Oxford Nanopore company has recently been pioneering a new way of sequencing DNA, by pulling it through a specific pore. The machinery required to do this roughly fits into the size of your palm, and is USB powered! It’s still a method in need of a lot of refinement, as recent studies show that it gets about 1 in every 25 bases wrong. However, it shows just how far these fields have come that a USB powered sequencer is even possible in an industry mostly dominated by dining table-sized machines costing millions of pounds.
Ultimately, don’t expect an affordable DNA powered USB stick any time soon. The paper published for these results estimates a 50 year period before DNA information storage starts to make economic sense, and have a real world advantage over normal hard drives. DNA based storage may be the ultimate storage solution of the future. For now, all it has is potential.
If you’re genetically minded, and want to know more about how all this is done, check out the paper ‘Toward practical high-capacity low-maintenance storage of digital information in synthesised DNA’.