"Unused DNA is kept in a high-density area, using the folding pattern within a pattern. This storage pattern is called a fractal globule. It enables the cell to store DNA in amazingly little space, avoiding tangles and knots that would destroy the cell's capacity to read its own instructions. The DNA quickly unpacks and repacks during gene activation and cell replication.
"'Nature's devised a stunningly elegant solution to storing information-a super-dense, knot-free structure,' says senior author Eric Lander, director of the Broad Institute, who is also professor of biology at MIT and professor of systems biology at Harvard Medical School.
"The globule is a lattice, a pattern known to mathematicians, in which every point is only visited once and no paths intersect. This prevents knots from forming.
"The Harvard Gazette reports, 'The human genome is organized into two separate compartments, keeping active genes separate and accessible while sequestering unused DNA in a denser storage compartment ... the information density in the nucleus is trillions of times higher than on a computer chip.' Cells move chromosomes back and forth between the two compartments as needed."
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