DNA Researcher's Job is a Stretch

Here's what biophysicist Carlos Bustamante of the Energy Department’s Lawrence Berkeley National Laboratory does for a living: twists and stretches DNA molecules with magnetic tweezers. He and other researchers figured that doing so would cause the DNA's famed double helix to unwind. But it turns out that's not true -- even if you take a DNA molecule from inside the nucleus of a cell, where it measures about a millionth of an inch across, and stretch it out to three feet in length.