Having enough reliable, fast, computer memory available is impossible. We always want more, and we always want it faster, and we want it to persist, and we want it to be cheaper, and we want it to be lower power... the list is long. It's been less than 100 years since we learned that evolution has been using a digital read/write memory for billions of years. It uses little power and it stores immense amounts of data with astonishing density and unheard of error correction systems. It is our DNA! And it's even more sophisticated than our two-level (binary) memory. It is a four level (quaternary) memory so it stores twice as much information per memory location. Not to mention that it's very structure allows it to do its own "backup"and at the same time provide error correction! I could go on, but I think you get the idea, DNA storage has to eventually become part of the evolutionary path for our computers.
Read This Book... in DNA
This isn't a new idea, people have been thinking about this for decades. In 2012 the Harvard Medical School announced that it had stored an entire book in DNA: George Church’s "Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves" (you have to love the recursive element). There is an interesting video and article about it here. And because of the easy and cheap DNA replication it only took a matter of days to make more than 70 billion copies. Oh, and they would fit on your fingernail.
An Interesting Twist
That effort was done four years ago in a Harvard research lab, but it looks like this technology is poised to take off big time. It seems that Microsoft is spending some serious money on this technology. It's been announced that Microsoft is working with Twist Bioscience and has purchased some prototype DNA storage sequences.
In the beginning the San Francisco based startup had positioned itself to create specific snippets of DNA that could be injected into existing organisms. One of their primary revenue targets was the petroleum industry where, for example, they could reengineer microorganisms to "digest" all of those inevitable oil spills. There is much more information about how Twist actually implements this technology in the IEEE Spectrum article here. The idea of repurposing this technology to store data could open a vast new market for Twist.
As a storage medium, DNA is not only durable, but also incredibly compact: A pea-sized lump of DNA can store about one zettabyte of digital data. As our technological culture generates unimaginable quantities of data we will need ways to store it. Today, much of the Internet is not archived, it just evaporates and is gone forever.
This technology is just in its infancy. It is still too complex and expensive to put in our laptops or tablets. Its first uses will probably be to archive data in much the same way that (five decades ago) tape drives were used to store off-line data. As the speed of access (and cost) improve it seems likely that this technology will move into a more active role in computation.
Remember when DNA sequencing began for the human genome the cost was about $1 billion per person and took the labor of many technicians and machines over many months. But in two decades the sequencing cost is around $1000 per person and an automated process does it in hours. It's always dangerous to extrapolate advances in technology too far, but it seems likely that we still have a ways to go with this technology. If these trends continue we should expect the cost to come down to pennies and the time to milliseconds.