"Water drop holds atrillion computers," by John Whitfield. Nature Science Update, 22November 2001.
The basic tools of computing can be found in the very stuff responsiblefor making us---DNA. Though simple computing devices have been made fromDNA before, a team of researchers has recently fashioned the first onethat works autonomously. This new computer takes a DNA strand as input,treating the letters as if they were a string of ones and zeroes, andanswers simple questions like whether the input string contains an oddnumber of zeroes. The hardware consists of two enzymes, one that cuts theDNA strand and another that sticks DNA pieces back together. Theseenzymes chomp through the strand according to the arrangement of DNAletters, until only one remains. This letter, interpreted as a one or azero, is the program's output.
--- Rafe Jones