CELL SPECIFICITY WITH SINGLE CODE. “Which proteins and RNAs are made when and where is not fully specified. This is why it is possible for the 200 or so different cell types in an organism such as the human to make those cell types using exactly the same genome. A heart cell is made using precisely the same genome in its nucleus as a bone cell, a liver cell, pancreatic cell, etc.”
http://rsfs.royalsocietypublishing.org/content/2/1/55