I am watching/listening to your Teaching Co. DVD lecture series on Human Evolution and very much enjoying it. I graduated from Beloit College in '68 with a BA in Anthro, and while I have tried to keep up with new discoveries, it has been haphazard. Your lecture series really helps me appreciate what huge progress has been made in this field since 1968. I recently retired from a career in Mental Health. I have wondered why schizophrenia is so common amongst humans and have thought it might be like sickle cell anemia. A very small dose of the schizophrenia complex of genes might be connected to our use of symbolism and creativity. A large dose might create the dysfunction of psychosis. Thanks for your research and for being able to express the material with such clarity and energy.
Thank you so much for your kind words! We put so much work into doing the best lectures possible, and I’m really proud of the result.
Your question about schizophrenia is one that really strikes at what evolutionary biologists are thinking about the subject. We’ve been thinking with our work on recent selection in human populations that we might find some selected genes with side-effects on cognition. Many human geneticists have been looking for genes that explain the risk of schizophrenia, and we know that there are a few common gene variants that affect risk. But it appears that most of the risk must be explained by gene variations that are found in one or a few families. It seems to be a case of “every unhappy family is unhappy in its own way.”
That makes it hard to find and understand the genetic causes, but as we move toward whole-genome sequencing and more and more observations on different families, we will begin to understand more about the causes.