[Mari]

http://www.nytimes.com/2010/11/09/health/09brain.html

Genes as Mirrors of Life Experiences

Studies suggest that such add-on, or epigenetic, markers develop as an animal adapts to its environment, whether in the womb or out in the world — and the markers can profoundly affect behavior.

By studying genes at the “epi” level, scientists are hoping to discover patterns that have been elusive at the level of the genes
— and ideally to find targets for calibrated treatments that would not simply shut off errant genes but would gradually turn their activity up or down, like adjusting the balance on a stereo.

M.