Archive for August, 2012

A new way to storage digital information?

Sunday, August 26th, 2012

Information, of all kinds, has been increasing since humans learned how to write in stones in ancient times. Now that there is an explosion of information, mainly digital information, we are in need of better ways to storage it in a safe and stable manner. One solution that is becoming reality is the “cloud”, a service that companies provide for information storage. Companies such as Apple, Dropbox, Google and other offer server space to store all types of digital information (books, movies, photos, etc) for a fair price. However, it looks like nature already had one simple and stable way to store data. A recent article in Science by Harvard Professor George Church (for more information see “Next-Generation Digital Information Storage in DNA”) demonstrates that indeed nature has a better way to do information storage using the DNA molecule. DNA has many potential advantages over other systems since it is very stable and most times immutable (except if exposed to mutagens that cause mutations in the bases, changing its sequence). Dr Church’s group developed a strategy that encoded the digital information of a whole printed book using a novel scheme of next-generation DNA synthesis and sequencing technologies. The group converted 53,426 words, 11 images and 1 Java Script Program into 5.27 megabit bitstream, that were encoded onto 54,898X 159 oligonucleoties (which are small pieces of DNA). After the codification the oligonucleotides were synthesized, printed and linked together to form a stable DNA molecule. The newly synthesized DNA was further sequenced to recover the information, which was done with success. This article is a milestone not just in storing information inside a biological molecule, but in showing that nature itself have smart ways to “save” and codify information. Well, DNA encode for entire cellular programs inside the cells of organisms. Importantly, we are still trying to decipher DNA’s cellular code since it is composed by different layers of information, not just the sequential bases of the “linear” DNA. Examples include chemical modifications in the DNA such as methylation or acetylation, which could change the meaning of specific regions. The fact is that DNA is very suitable for immutable, high-latency, sequential access applications such as archival storage – cells already utilize it. So, why we did not think about using DNA to store information before? Mainly because now we have all the technology to do it, before we did not. We can synthesize long stretches of DNA, print it on glass slides and also sequence it fast, since DNA sequencing technologies are evolving faster than the speed of computers. In fact, Moore’s law does not apply to DNA sequencing. The costs of DNA synthesis and sequencing have been dropping at exponential rates of 5- and 12- fold per year, respectively. This is much faster that electronic media, that is just 1.6- fold a year. Additionally, DNA has other advantages such as density, stability and energy efficiency to store information. I believe this might be just the start for digital information to be stored in the DNA molecule. Information will continue to accumulate; long-term and stable solutions like the one presented by this group will be able to store it. The take home message is that nature is teaching us – the tools are already here, we just have to learn how to use them.