Beyond the double helix

摘要

Every day, as a young postdoc, Susan Gasser gazed at a twisted wire skele-ton of DNA that was collecting dust in her supervisor's office―a sculptural homage to Jim Watson and Francis Crick's epoch-making paper on the double helix. But Gasser now heads a molecular biology laboratory at the University of Geneva, whose members see DNA in a very different light. By shooting microscopic movies of clumped DNA in the heart of living cells, Gasser and her colleagues have shown the molecule to gyrate like a demonic dancer. For Gasser, the iconic image of DNA as a static double helix is somewhat passe: she's now fascinated with the significance of its endless acrobatics. "The way I think about DNA is different," says Gasser, who is not alone. Watson and Crick transformed biology by revealing the three-dimensional structure of DNA―and in so doing, set the stage for a lasting obsession with its sequence of chemical letters. But 50 years on, researchers are realizing that DNA has a fascinating life in three dimensions―and the fourth dimension of time―that makes it far more than a simple string of code.