Number 171 (Story #1), April 1, 1994 by Phillip F. Schewe and Ben Stein|
FASTER TECHNIQUES FOR SEQUENCING DNA , described at the American Physical Society (APS) March Meeting in Pittsburgh, may contribute to the Human Genome Project. With the conventional technique, known as gel electrophoresis, in which DNA fragments are separated by electric fields, it would take 20,000 man-years to determine the complete sequence of 3 billion "base pairs" that make up the human genetic code. In a modification of electrophoresis that uses thinner gels and higher electric fields, Lloyd Smith of the University of Wisconsin can now sequence a 500 base-pair DNA fragment in an hour, as opposed to the 12-14 hours it takes normally. Brian Chait of Rockefeller University has devised a sequencing method that completely bypasses the use of a gel. In his method, a laser pulse would zap DNA fragments, converting them into gaseous ions which would then fly towards a detector to be analyzed. Once his technique is refined, Chait estimates that an amount of DNA code that normally takes several hours to sequence could be analyzed in less than a minute. Other researchers in Pittsburgh proposed sequencing methods based on photolithography techniques and single-molecule detection.