I can't explain the paper, but if DNA is genetic ROM, methylation is like one bit of RAM available on each digit [*]. Most of the cellular machinery tries pret

I can't explain the paper, but if DNA is genetic ROM, methylation is like one bit of RAM available on each digit [*]. Most of the cellular machinery tries pretty damn hard to make exact copies of DNA. The methylation bits, by contrast, get deliberately flipped on and off all the time. [*] Technically only A and C can accept methylation, but in a double helix you'll always have either an A or a C on one side or the other at every position (A pairs with T, C pairs with G).