Epigenetics

I've long thought we are more nature then nurture, but since reading Survival of the Sickest I've been developing doubts.  

The reason is epigenetics, which is the study of changes in the expression of genes because of factors in our environment - sort of a layer above genetics that can have immediate impact AND may be immediately inherited.  It seems our nature is less like a blue-print and more of a collection of dynamic feedback systems with our environment being part of the loop.  If true, this would tend to make us hyper-adaptive and maybe explain some of the mysteries of evolution.

Here's an example:

Gene switches make prairie voles fall in love