Forget CDs, memory sticks or hard drives: it seems the quintessential molecule of life – DNA or deoxyribonucleic acid – may be the digital storage medium of the future.
Exactly 60 years ago this month, James Watson and Francis Crick burst into the pub next door to their Cambridge laboratory to announce the discovery of the "secret of life". Now scientists are moving beyond understanding how DNA stores genetic information and applying it to other areas, such as long-term storage of digital archives.
Writing in the journal Nature, a team of researchers from the European Bioinformatics Institute (EBI) at Hinxton, near Cambridge in the UK, have described how they encoded a PDF of a scientific paper, Shakespeare’s sonnets, a 26-second excerpt from Martin Luther King's ‘I Have A Dream’ speech, and a photograph in artificially produced segments of DNA.
The DNA used for the storage was no bigger than a speck of dust but held the equivalent of 739 kilobytes of hard-disk storage. Appropriately, the PDF was the original 1953 paper by Crick and Watson that first set out the structure of DNA.
The scientists synthesized the DNA, sequenced it and reconstructed the original files with 100% accuracy.
What’s more, the technique is scalable, according to the team. DNA is perfect for storing not just genetic code but other types of information because it is very stable, robust and a fantastically dense storage medium – one gram of DNA will hold the equivalent of three million CDs.
It is possible to store huge volumes of data in DNA for thousands of years and without any electricity to maintain its storage function. EBI’s Dr Ewan Birney explains: "If you keep it cold, dry and dark, DNA lasts for a very long time. We know that because we routinely sequence woolly mammoth DNA that is kept by chance in those sorts of conditions."
Furthermore, the technology is likely never to become unreadable given DNA’s status as a fundamental molecule of life on earth.
Although DNA storage is prohibitively expensive at the moment, prices should come down to make this an attractive option for long-term and, importantly, maintenance-free archiving.
Among the applications for DNA storage is any type of information that must be retained but doesn’t need to be accessed every day. This includes government archives and historical records.
So, how does it work? The DNA codes the information using the same four nucleotides – guanine, adenine, thymine, and cytosine – as with genetic material but translated in a way that cells wouldn’t understand. The system converts binary computer code into a bespoke code, which is then sequenced by a standard DNA synthesis machine.
The UK team is not the first to see the advantages of DNA archival: last year, a group from Boston described in Science magazine how they laid down a whole book using DNA sequencing. However, the UK group has gone further towards addressing issues of scalability and practicality.
Did you know? Building on the work of many scientists, Watson and Crick’s
discovery of the structure of DNA was also made possible by advances in model building, specifically the assembly of possible three-dimensional structures based upon known molecular distances and bond angles, a technique advanced by American biochemist Linus Pauling.