The computers of tomorrow may be constructed from the same building blocks that are inside of you. Merging insights from the fields of molecular biology, computer science, and mathematics, professor Lila Kari of the University of Western Ontario is looking into the possibilities of DNA computing.
A computer need not be made of electrical parts. A computer can be constructed from anything, so long as it is able to perform two functions: store data, and perform certain arithmetic and logic operations on it.
Kari is currently investigating the way in which data can be encoded using the DNA alphabet, which consists of four building blocks commonly labelled A,C,G and T. Techniques from molecular biology, including the ability to insert and delete genetic information, are used to perform arithmetic and logic operations.
Genetic material is very tiny, so there are a lot of advantages. The secret, according to Kari, is “information density…because DNA strands are so small, you can have many working together at once.” DNA computers could be up to a million times faster than an electronic computer. “To encode the same information that can be stored in 1 gram of DNA would take a trillion CDs,” says Kari.
Back in 1994, Len Adleman at the University of Southern California solved a difficult problem, known as the “travelling salesman problem” through DNA computing. The problem involves trying to figure out the shortest route one could take in order to travel to a certain number of cities. “If you have a network of 200 cities, the number of possible solutions is greater than the number of atoms in the universe,” Kari explains.
It is the exact kind of problem that DNA strands could solve. The method involves assigning a DNA strand to represent each city. Then taking advantage of the way two DNA strands will stick together, other “route” strands, being complementary to two city strands, will connect cities together. As the strands jostle around, the random results are sifted based on length to find the minimum route that connects all city strands.
Nanobiotechnology seeks to use these computational abilities to create programmable cells that could be used for a variety of computational and medical purposes. Four years ago professors Kari and Laura Landweber, who is now an associate professor of ecology and evolutionary biology at Princeton, began working towards reprogramming a cell’s functions.
“Our grandiose goal is to make a programmable cell,” says Kari. This way cells could perform all the processes of a conventional electronic computer with all of the advantages inherent to biological systems.
