Potential of a DNA computer

Microchip manufacturers have been entangled in a constant race to come up with faster processors that eat up more bytes of data for less money. Today a high-end home computer can beat the rhythm at 2 Giga hertz, and in accordance with Moore's Law, the number of electronic devices put on a microprocessor has doubled every 18 months. Moore's Law is named after Intel founder Gordon Moore, who predicted in 1965 that microprocessors would double in complexity every two years. Many have predicted that Moore's Law will soon reach its end, because of the physical speed and miniaturization limitations of silicon microprocessors. This has made everyone look beyond silicon to find new material to produce faster computers, but the 'new material' they have found is quite remarkable, to say the least.

Millions of natural supercomputers exist inside living organisms, including our own bodies. DNA (deoxyribonucleic acid) molecules, the material our 'genes' are made of, have the potential to perform calculations many times faster than the world's most powerful human-built computers. DNA might one day be integrated into a computer chip to create a so-called biochip that will push computers even faster. I am not writing about a dream I had last night. In fact, DNA molecules have already been harnessed to perform complex mathematical problems!

The technology is still being developed, and didn't exist even as a concept a decade ago. In 1994, Leonard Adelman introduced the idea of using DNA to solve complex mathematical problems. Adelman, a computer scientist at the University of Southern California, came to the conclusion that DNA had computational potential after reading the book, 'Molecular Biology of the Gene', written by James Watson, who co-discovered the structure of DNA in 1953. In fact, DNA is very similar to a computer 'hard drive' in how it stores permanent information about your genes.

Researchers at the University of Rochester developed 'logic gates' made of DNA. Logic gates are a vital part of how your computer carries out functions that you command it to do. These gates convert the binary code moving through the computer into a series of signals that the computer uses to perform operations. Currently, logic gates interpret input signals from 'silicon transistors' and convert those signals into an output signal that allows the computer to perform complex functions.

The Rochester team's DNA logic gates are the first step towards creating a computer that has a structure similar to that of an electronic 'PC'. Instead of using electrical signals to perform logical operations, these DNA logic gates rely on a DNA code. They detect fragments of genetic material as input, splice together these fragments and form a single output. DNA computer components — logic gates and biochips — will take years to develop into a practical, workable DNA computer. If such a computer is ever built, scientists say that it will be more compact, accurate and efficient than conventional computers, and unlike the toxic materials used to make traditional microprocessors, DNA biochips can be made cleanly.

DNA computers would also be many times smaller than today's computers. DNA's key advantage is that it will make computers smaller than any computer that has come before them, while at the same time holding more data. 

One pound of DNA has the capacity to store more information than all the electronic computers ever built; and the computing power of a teardrop-size DNA computer, using DNA logic gates, will be more powerful than the world's most powerful supercomputer. More than 10 trillion DNA molecules can fit into an area no larger than 1 cubic centimetre (0.06 cubic inches). With this small amount of DNA, a computer would be able to hold 10 'terabytes' of data, and perform 10 trillion calculations at a time. By adding more DNA, more calculations could be performed.

Unlike conventional computers, DNA computers perform calculations parallel to other calculations. Conventional computers operate linearly, taking on one task at a time. It is parallel computing that allows DNA to solve complex mathematical problems in hours, whereas it might take electrical computers hundreds of years to complete them.

The first DNA computers are unlikely to feature word processing, 'e-mailing' and solitaire programs. Instead, their powerful computing power will be used by national governments for cracking secret codes, or by airlines wanting to map more efficient routes. So much for dreaming what the world will be in a couple of decades!