Here comes my most favorite paper in 2010 so far, clearly written and elegant in it’s simplicity. It is printed in this week’ Nature magazine
One reason for this is that epigenetic factors are sometimes malleable and plastic enough to react to cues from the external and internal environments. Such induced epigenetic changes can be solidified and propagated during cell division, resulting in permanent maintenance of the acquired phenotype.
Petronis sees heritability as multiple layers (like a Russian matryoshka doll) which is a far more appropriate view than the current DNA sequence based view.
The paper touches many points that I will also include in a forthcoming review where I am describing epigenetics as a buffering system before changes are permanently written in the genome, yea, yea.