Philosophers, psychologists and scientists have long debated whether our behavior is largely the product of environmental influences (nurture) or mostly the consequence of our genetic make-up (nature). Modern discoveries in biology have confirmed the suspicion of many that it's probably a combination of both.
Research on rats suggests that environment can actually change an animal's genome (the genetic composition of an organism) and thus influence much of its behavior.
The part of the genome that appears to be affected by environmental factors is not the actual DNA, which is the chemical basis for our genes, but rather molecular tags (called methyl groups) that attach along the DNA and act as switches turning certain genes on and off.
These tags are collectively referred to as the "epigenome," and this five minute video explains how it's believed that the environment affects these elements of our genetic make-up.
The mystery, at least it's a mystery to me, still remains how the proteins coded for by our genes translate into behavior. How do strings of amino acids generate a behavior like licking the young, building a specific type of nest or migrating to a specific tree thousands of miles away (see yesterday's post)?
There must be some connection between physical proteins and an organism's behavior, but if it's known I've never seen it explained.