This is quite interesting: A. Feinberg and R. Irizarry, from John Hopkins University (Maryland, USA), have been researching epigenetics in mice and found some curious implications, not known before.
Rapid adaptation to changing environmental conditions (new disease variants, for example) can hardly be achieved by mere genetic change, which is just too slow. Similarly, genes that cause certain diseases (like schizophrenia or diabetes) are also proving virtually impossible to find (as natural selection would wipe them out).
Epigenetics offers potentially alternative explanations to such crucial problems in the field of genetics. However it is a very new field and it is unclear how inheritable are such modifications.
Feinberg and Irizarry have found with their research that epigenetic modifications (methylation, etc.) affect certain specific batches of genes, more open to such environmental modification, but not the rest (these regions were also found to be the same in humans). They also found that mice with the same upbringing had different individual methylation patterns in some regions, specifically regions that are responsible for anatomy in early development (goodbye anthropometry?)
The Maryland scientists also modelled in a computer simulation a hypothetical variable Y component within an equally hypothetical population. When the environment was stable, this variable Y factor was detrimental to survivality but, when it changed periodically (as happens in reality), it favored the survivality by creating indivduals with a wider range of characteristics.
This variability, biologically implemented by epigenetic mechanisms, seems able to explain a good deal of the otherwise unexplained variability in humans and other animals, both for good and bad.
Read more at Science Daily. Not sure if the paper might be this one or is still in preparation.