We typically think of Darwinism when discussing genetics and inheritance, but more and more it is becoming obvious that there is Lamarkian epigenetic inheritance as well. Not only are genes heritable, but gene expression patterns. And those gene expression patterns are determined by one's environment. In other words, the environment affects my gene expression patterns, and those gene expression patterns are then inherited by my children. We have known about epigenetics -- particularly DNA methylation (something I was fascinated with when I was actively studying molecular biology in college) -- for a while now, but it has only been recently that much attention has been paid to it. The human genome project seems to have had a huge influence on these developments, since the number of active genes seemed bizarrely small for such a complex organism as human beings. What gives? Well, there are all sorts of regulatory differences,and mong them are epigenetic influences as well.
What does epigenetic inheritance have to do with understanding human nature, evolutionary psychology, and literature? It may be too early to know. But it's never too early to keep an eye out for such research, to be familiar with such effects, to keep abrest of the latest developments. Epigenetics is very important -- we just don't know to what degree, or how it affects human behavior. Yet.