Physics @ Berkeley
Physics in the News
Title: Surprise Finding For Stretched DNA
URL: http://www.lbl.gov/Science-Articles/Archive/PBD-stretched-DNA.html
Date: 08/07/2006
Publication: Research News, Berkeley Lab
Editor: Lynn Yarris (510) 486-5375, lcyarris@lbl.gov
Extended Text:

BERKELEY, CA ó Most of us are familiar with the winding staircase image of DNA, the repository of a biological cellís genetic information.  But few of us realize just how tightly that famous double helix is wound.  Stretched to its full length, a single molecule of human DNA extends more than three feet, but, when wound up inside the nucleus of a cell, that same molecule measures about one millionth of an inch across. Biologists have long believed that as a molecule of DNA is stretched, its double helix starts to unwind.  As much sense as this makes from an intuitive standpoint, a recent experiment proved it not to be the case.