DNA Computing

In Star Trek: The Next Generation, one of the scientists coded and stored his information in RNA sequences. Crazy idea? Not really. Just think of how much information is stored in the 3.5 billion base pairs of our chromosomes. "Intelligent" molecular complexes have been synthesized that can assemble themselves into predetermined structures with varying degrees of complexity. Dr. Adeleman (Scientific American, August 1998), a mathematician, illustrated how information can easily be coded as DNA sequences. This knowledge could lead to the development of molecular computers.

Molecular computers have many potential advantages over our electronic computers. According to Dr. Adeleman, molecular computers offer these advantages:

1. One gram of DNA can store as much information as one trillion CDs. (Each CD can store 650 MB of data.)
2. A molecular computer is very energy efficient. One joule of energy will allow for 2 to 34 x 10¹⁹ ligations where as an electronic computer will execute only 1 x 10⁹ operations per joule.
3. They are quick. Billions of nucleotides sequences can be linked together in less than 1 second.

The secret to these advantages are the coding sequences of DNA and the properties of enzymes involved in DNA synthesis.

• What properties of enzymes allow them to work so efficiently, so quickly and without very much energy?
• Of the four nucleotides that make up DNA, how many distinct codes could you make from a sequence of 10 nucleotides?

Molecular computers in the future are a distinct possibility.