Using a mathematical model known as the Ising model, invented to describe phase transitions in statistical physics, such as how a substance changes from liquid to gas, the Johns Hopkins researchers calculated the probability distribution of
methylation along the genome in several different human cell types, including normal and cancerous colon, lung and liver cells, as well as brain, skin, blood and embryonic stem cells.
Next, they found that the
genomes of naïve embryonic stem cells have less
methylation — the addition of methyl chemical groups
along DNA.