The DNA Hard Drive

A,C, G, and T. Every biology student learns that the information to construct a cell is contained in those four letters, and each corresponds to a chemical nucleotide. These nucleotides contain the information for the formation of a polypeptide, which in turn conduct the operations of a cell. Sound familiar? Actually, it sounds a little boring – unless of course, scientists could generate a DNA storage device, something right out of a science-fiction movie.

How does information storage work? In a typical computer, each “bit” of information can be stored in one of two states, a 1 or a 0. By building long chains of 1’s and 0’s, it is possible to store significant amounts of information. The stored information (either on a hard drive, RAM, or some other digital devide) is then “read” by a program that makes sense of each piece of data. Want to see this at work? Open up the contacts page on your cell phone and select a phone number – all of that information is stored as digital 1’s and 0’s.

There is only one problem, technology is reaching the limit of the storage capacity for these types of devices. Technology is still limited by the fact that each spot in the code can still only record one piece of data. Imagine writing a term paper using only 2 letters – to get a simple sentence constructed may take several pages. There is a better system though, one that has been in use for a little over 4 billion years – DNA.

Each location in the DNA contains one of four possible bits of information – these same A, C, G and T molecules (Animation : DNA Structure). The double-helix nature of DNA gives the molecule stability, and, it can be compacted into a really, really small location – the nucleus.

 

DNA structure

Mader/Windelspecht Essentials of Biology 3e – used by permission

 

Life figured out a long time ago that DNA was the ultimate storage mechanism. And now, science and technology are catching up. Researchers at Harvard University have developed a procedure that can store the entire contents of a genetics text book (Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves,)  in just a small amount of DNA. Their procedure, using recent advances in DNA sequencing and retrieval that increased the ability to store information as genetic code. Of course, DNA also has the ability for replication. So, it may be possible one day to insert information into a cell, and then let normal cellular reproduction take over. In a short period of time, you may have millions of copies of your textbook!

What is the potential of using DNA as a storage media? Think of how much data is generated across the globe each year – everything you touch digitally, all of your phone calls, everything that contains an electronic signature. It is estimated that all of this data, for everyone, could be stored on just 4 grams of DNA. to put this in perspective, most DVDs (without the case) weight around 17 grams. Thus, the same DVD, if it was an equivalent amount of DNA, could hold all of the data generated by humans for 4 years!!

There are some drawbacks – mostly in the fact that storing the information in DNA code is not hard, but retrieving it is a little more problematic. Unless of course, you are a cell, then you already have a complete set of tools to express your genetic information!  So, at the moment, DNA hard drives (when available) would probably be better used as long-term storage devices. But, if they could be coupled to digital input/output devices, then it may soon be possible to store the entire knowledge of the human race on your cell phone.

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