DNA is an incredibly efficient way to store data: It can store billions of base pair “bits” — the entire set of instructions to make a whole human, in a single, microscopic cell. While a computer stores information as ones and zeros, in DNA data storage the four nucleotide bases (A, C, G, T) store and encode data. Our genes are simply long or short runs of sequences of those bases.
In addition to increasing data storage density, there are other advantages to DNA data storage as well. Traditional magnetic tape needs to be rewritten every ten to twenty years. DNA, on the other hand, lasts one hundred, two hundred years, or even longer — it really depends on how you store it. Perhaps even more important for preserving information for future centuries or even millennia, is that DNA is always going to be around. One day, we might not have machines capable of reading VHS tapes or CDs or even today’s hard drives. But the same thing probably won’t happen with DNA.
Despite all the advantages presented by DNA for data storage, we have not yet replaced our hard drives with tubes of DNA due to the considerable limits still present on this technology. The principle limiting factors are the speed and the cost of DNA synthesis. This process is estimated to cost more than 3000 dollars per megabyte of information. That is why, while many researchers are planning to store data-containing DNA on chips, others are exploring the potential of storing it within the genomes of living organisms.
Already today there is a system encoding data directly into the DNA of living bacterial cells using CRISPR. Although this would result in less-dense data storage, since there’s only so much extraneous DNA you can add to a cell’s genome, it would also make it very easy to make copies of the data because frozen or freeze-dried cells could be pulled out and allowed to copy themselves many, many times over. Furthermore, some bacteria can form spores which are highly resistant to heat, radiation, and chemicals, meaning that data stored in particular types of bacterial DNA could be much less vulnerable than data stored by synthetic DNA on its own. Frozen spores could last more or less indefinitely. Apparently, in the future, using cells to store data could also help reduce the costs of writing information into DNA, because cells are already equipped to make all of the enzymes and raw materials needed for DNA synthesis, they just need to be given food and the appropriate growth conditions.
One day, researchers say, living cells could also actually record information about their environment in their DNA. One especially interesting environment could be the human body. Although researchers are still figuring out exactly how to do this, it’s possible that a cell’s natural abilities to sense certain chemicals, for example, could be hooked up to some type of CRISPR system which would modify the cell’s DNA in specific patterns whenever the cell sensed a given chemical. This would allow living cells to record information about what’s happening in the body in real time, and write it into their DNA so that this information could be read later. To be honest, it sounds a bit creepy to me…
Unfortunately, it will be quite some time before DNA storage is a commonplace and affordable storage option available to the public, so today a full transition towards the use of DNA as a method of data storage, or the idea of a computer based upon such a method, remains an utopia.