Years from now, when your state-of-the-art PC is on the fritz, you might have to call your local molecular biologist for tech support. If you think that’s a stretch, think again. Scientists are hard at work, attempting to use DNA as the next processing power for computers of the future.
Sure, computer-chip manufacturers are burning the midnight oil developing the next microprocessor to topple current speeds. But if you subscribe to Moore’s Law — Intel founder Gordon Moore’s assertion that personal computer speed doubles every year — then microprocessors made of silicon will eventually reach their limits in speed and miniaturization. That means producers will eventually need new materials to power PCs. In addition to DNA, scientists are also considering “quantum computing” and other such Star Trek-like solutions. And while DNA is perhaps the last substance that comes to mind when you think of your desktop or laptop, it does have the potential to perform calculations faster than today’s most robust computers while storing colossal amounts more data.
So how did we get from PCs to DNA? The movement began about eight years ago when Leonard Adleman, a computer scientist at the University of Southern California, introduced the idea of using DNA to solve complex mathematical problems. Adleman’s findings and past research show that DNA is similar to computers in the way it stores permanent information about our genes. Helping give credence to the movement, he also discovered that one gram of DNA can hold as much data as one trillion CDs — that’s a lot of MP3s. Adleman used his DNA computer to solve the Hamiltonian Path problem that most of us likely encountered in junior high or high school math class. Also known as the “traveling salesman” problem, the goal is to find the shortest route between seven cities going through each only once.
So how does this Star Trek-meets-Fantastic Voyage technology work? First, because it’s in its infancy, most existing DNA computers consist of only synthetic, made-to-order DNA strands attached to gold plates on one end, with the other end floating freely in test tubes or petri dishes that are linked to myriad scientific devices in university labs. Second, the most rudimentary explanation of operation is, just as current hardware or software is programmed, so are made-to-order, synthesized, single DNA strands. “DNA is composed of four basic building blocks: A, C, G, and T,” says professor Lila Kari, research chair in bio computing at the University of Western Ontario in London, Canada. “DNA is just like an alphabet. In the same way you can use the alphabet to write, say, communist propaganda or Walt Whitman poems, you can use it to write human genes or to write numbers.”
When these single strands are placed in the proper solution and environment, they seek out their complementary counterpart, thus helping to perform the required calculation or task in what amounts to “contents addressable storage.” In a task such as finding the balance in a banking account, one strand with the account holder’s personal information seeks