"With regard to the immediate question, there is certainly a large set of observations which indicate that genes influence personality. And, given the availability of new molecular techniques, one ought to expect substantially more observations of this kind in the years to come. In the face of that, what needs to be kept in mind is that the observations show that genes influence personality. They do not, and cannot show that genes determine personality. Even many scientists tend to confuse the two sorts of conclusions, presuming that an observation showing something to be influenced by one thing necessarily implies that other things are irrelevant. This is simply not the case. In general, biological phenomena are influenced simultaneously and to varying degrees by a variety of factors, and there is abundant reason (both in principle and in terms of additional observations) to believe that this is true for personality.
"If one started with a belief that personality is totally a function of environmental influences--as many people do--then one has some useful and appropriate things to learn from the growing evidence for genetic influences. Genes do influence personality, as they do intelligence and every other aspect of being human. What they don't do, for personality or any other aspect of being human, is to determine it.
"Not only environmental influences but also personal dreams and choices demonstrably play a role as well. Wisdom is to be found not in the latest scientific observations, nor in the most visible ones at any given time, but rather than in their totality...and in a recognition of the complex web of causal interactions and personal responsibilities which that implies.
"The citations in this response are part of a website maintained by myself and a group of colleagues as a resource for people interested in brain, behavior and education.