Cells are tidy packers, cramming DNA into nuclei to create a tangle-free, dense ball with pieces that are still accessible, researchers report October 9 in Science. The findings, based on a new three-dimensional view of the whole human genome, solve a long-standing biological mystery and may lead to a deeper understanding of how genes operate.
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Except during division, a human cell’s two meters of DNA is jammed into an area about a hundredth of a millimeter wide. But researchers had been puzzled by how cells could pack the DNA, which is organized into 23 pairs of chromosomes inside the nucleus, so tightly without hopelessly tangling it and making it impossible to use.
“This paper is truly outstanding because it solves a problem that’s been around for a long time,” comments physicist and polymer expert Gene Stanley of Boston University. “It’s the question any child would ask — how does all of this DNA fit into the cell?”