Scientists Say They’ve Found a Code Beyond Genetics in DNA - New York Times: "Researchers believe they have found a second code in DNA in addition to the genetic code.

In a living cell, the DNA double helix wraps around a nucleosome, above center, and binds to some of its proteins, known as histones. The genetic code specifies all the proteins that a cell makes. The second code, superimposed on the first, sets the placement of the nucleosomes, miniature protein spools around which the DNA is looped. The spools both protect and control access to the DNA itself."