A LIVING COMPUTER

• Imagine a computer so small that one cubic centimeter could store as much information as one trillion CDs.
  
• Imagine a computer so fast that a teaspoon-sized computer could complete 1,000,000,000,000,000 links in a second.
  
• Imagine a computer so efficient that is would require less than a millionth of the energy used by current computers.

What you have imagined is a world where computers run not with traditional electrical connections, but with molecular connections of DNA.

After spending time in a molecular biology lab, computer scientist Leonard Adleman realized something that the cell has known for millions of years: A molecule of DNA is a great way to store a whole lot of information. He also realized that two enzymes, ligase and nuclease, could act upon the DNA much like a program acts on information stored in a computer.

Adleman set out to build the first molecular computer and to use that computer to solve a problem. To store information for his computer, Adleman combined manufactured adenine, thymine, guanine, and cytosine in a test tube. Then he added the enzymes ligase and nuclease to "run the program." Finally, a tiny jolt of electric current isolated the DNA into readable "bands."

The problem Adleman chose to solve with his molecular computer was to find the best flight path between a set of cities. Specifically, this is a problem, known as the Hamiltonian Path Problem, that had not been efficiently solved by a traditional computer. Adleman's molecular computer solved the flight path problem in less than a second.

A generation ago, few people realized that almost all of today's school children would know that computers are comprised of one simple electronic choice, ZERO or ONE, repeated millions of times. Even fewer realized that almost all high school students would know that all the information that goes into a living organism is comprised of just four simple bases: adenine, thymine, guanine, and cytosine, or more familiarly A, T, G, and C, also repeated millions of times.

Only a few people of your generation now realize that their children may be learning to program a powerful computer made of DNA. And yet, this molecular computer may well change your future even more than some of the other great discoveries of science.

For more information, visit these Web sites

Scientific American 8/98
http://users.aol.com/ibrandt/dna_computer.html

Leonard Adleman
http://
www-hto.usc.edu/people/adleman_intro.html

Hamiltonian Path Problem
http://dna2z.com/dnacpu/dne1.html

 

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