The human genome - the 3 billion chemical letters strung alongside one another like popcorn on a thread - has, historically, been thought of as the body's blueprint. Almost everyone thought DNA held all the information required for a single-celled embryo to develop into a human and not a bumblebee…
"The genes that make our liver are the same genes that make our eyeballs, the same ones that allow us to play chess, enjoy Bach, or get drunk and get a tattoo," says Michael Meaney, a researcher at McGill University who works as a neurobiologist and clinical psychologist.
The other level of control is responsive. Scientists around the world are studying it in earnest. It allows a fixed genome - the cookbook -to adapt to a dynamic world, says Moshe Szyf, a molecular biologist at McGill University.