Beyond Silicon Computing DNA Computers:
Ever since scientists discovered that conventional silicon-based computers have an upper limit in terms of speed, they have been searching for alternate media with which to solve computational problems. That search has led us, among other places, to DNA. The advantage of DNA is that it is tiny, cheap, and can react faster than silicon. Since this fledgling field is only eight years old, it is difficult to guess at this stage what applications it may ultimately have. For now it is a terrific example of basic research, bringing together researchers from two traditionally disparate fields-computer science and biology-to find new approaches to doing creative science.
Electronic computers are only the latest efforts to use the best technology available for performing computations. Electronic computers have their limitations: there is a limit to the amount of data they can store, and physical laws dictate the speed thresholds that will soon be reached. One of the most recent attempts to break down these barriers is to replace, once more, the tools for performing computations with biological ones instead of electrical ones: enter DNA.
DNA and RNA computing (also sometimes referred to as biomolecular computing or molecular computing) is a new computational paradigm that harnesses biological molecules to solve computational problems. Research in this area began with an experiment by Leonard Adleman, a computer scientist at USC.
The main idea is the encoding of data in DNA strands and the use of tools from molecular biology to execute computational operations. Besides the novelty of this approach, molecular computing has the potential to outperform electronic computers. For example, DNA computers may use a billion times less energy than electronic computers, while storing data in a trillion times less space. Moreover, computing with DNA is highly parallel: in principle there could be billions upon trillions of DNA or RNA molecules undergoing chemical reactions, that is, performing computations, simultaneously. Some advantages of DNA are that it is both self-complementary, allowing single strands to seek and find their own opposite sequences, and can easily be copied. Also, molecular biologists have already established a toolbox of DNA manipulations, including restriction enzyme cutting, ligation, sequencing, amplification, and fluorescent labeling, giving DNA a head start in the arena of non-silicon computing.
Despite the complexity of this technology, the idea behind DNA computing springs from a simple analogy between the following two processes, one biological and one mathematical:
(a) the complex structure of a living organism ultimately derives from applying sets of simple instructed operations (such as copying, marking, joining, inserting, deleting, etc.) to information in a DNA sequence,
(b) any computation, no matter how complex, is the result of combining very simple basic arithmetic and logical operations.
Adleman realized not only that the two processes are similar but that advances in molecular biology allow one to use biology to compute. More precisely, DNA strands can encode information while molecular biology laboratory techniques provide simple operations.
So far a few labs have successfully designed protocols that use DNA or its chemical cousin RNA to solve classic computational problems, with efforts mounting not only in the U.S. but in Japan, Canada, and Europe. The long-term possibilities are endless but it is difficult now to see just where they will take us.
Working of DNA Computer :
DNA is the major information storage molecule in living cells, and billions of years of evolution have tested and refined both this wonderful informational molecule and highly specific enzymes that can either duplicate the information in DNA molecules or transmit this information to other DNA molecules.
Instead of using electrical...
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