A little speech about disease and genes from Tom Boyce MD, Professor of Pediatrics at the University of British Columbia. On the CBC “Ideas” program, starts around 17:30.
http://www.cbc.ca/ideas/episod…
Here is an interesting example about the interaction of nature and nurture, which work together in a “multiplicative” way that defies our linear idea of how you get a certain health condition or disease.
When we bring children into a labaoratory and ask them to go through challenging tasks, that show very highly variable behavioral responses to these laboratory challenges. We call this stress reactivity, and we know that it is at least in part genetically determined. But the outcomes for children in the studies that we have done seem to be driven by how reactivity and naturally occurring stress work together with the environment.
So if we look at a variety of outcomes in human children, sever behavior problems that can be the prelude to real psychiatric difficulties, if we look at an infection like respiratory illness, or if we look at non-intentional injuries and we look at these withing two different kind of social contexts, those that are stressful and those that are supportive here is what we find.
When we look at the children who are low in reactivity in the lab, they are relatively indifferent with respect to whether they are growing up in supportive versus stressful environments. There’s a little bit of increase in the rates of these kinds of problems in bahvior, infection or injury, but really minimal, and there’s really no significant difference between the supportive condition and the stressful condition.
By contrast to that, the children who show high reactivity in the laboratory situation show the worst outcomes of all when they’re growing up in naturally stressful conditions, but they also show the best of all possible outcomes, even lower than their low-reactivity peers, when they’re growing up in supportive environments. So they have either the worst or the best of the outcomes, depending upon the social context in which they’re being reared.
So the mental and physical health of school children appears in these studies to depend upon both their biological sensitivity to social context which comes at least in part from genes and the rearing circumstances in which they’re being raised.
He goes on to describe the chemical covering of DNA and the way environment may change that, and how that might affect the expression of genes on the DNA.
