How (and why) to find a needle in a haystack
The proper functioning of organisms depends on a complex game of hide-and-seek conducted inside the cell. Biologists are now beginning to draw on information theory to develop a better understanding of the rules of this game
SUPPOSE you really had to find a needle in a haystack. How would you do it? And how big would the needle have to be for you to be in with a chance of finding it? These may seem like silly questions. But a version of this problem occurs at every moment within the cells of organisms. Here, “you” are a protein molecule with the vital job of switching genes on and off; the “haystack” is all of the DNA in the cell; and the “needle” is a particular fragment of DNA, often not longer than five or six genetic letters (out of, in the case of humans, roughly 3 billion) that the protein must find before it can do its job.
This article appeared in the Science & technology section of the print edition under the headline “How (and why) to find a needle in a haystack”
From the April 5th 1997 edition
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