Evolutionary Medicine

Do we all lie on a continuum — from autism to schizophrenia?

Here is a provocative view of a continuum in social brain development by Bernie Crespi at the interesting Evolutionary Medicine symposium at Stanford yesterday.

“There are 1000s of genes for the social brain, and from the gene replication/deletion studies, the large perturbations are in opposite directions for autistics and schizophrenics. So far, the studies have been done in complete isolation from each other.”

“Some of the exciting new drugs, like those targeting mGluR5, have opposing agonist/antagonist approaches for treating schizophrenia and autism.”

“Why did evolution lead to these conditions? It is a classic case of pleiotropy, having too much of a good thing. The schizo genes are better at certain task like verbal skills and the autistic has better systematizing skills.”

Some of the other talks I really liked:

• Joon Yun’s summary of paradoxical medicine and trait induction (triggering the body’s compensation mechanism with an antagonist – like raising the heart rate with exercise with the goal of lowering the resting heart rate) as it relates to evolutionary maladaptation of the vagal autonomic nervous system in response to the shifting environment of modernity (less tiger bites, more heart failure). Joon is from PAI and organized this brain spa.

• Kari Nadeau’s summary of the epigenetics of food allergies, leading to a predictable doubling of prevalence in 20 years. When one parent has a food allergy, 65% of the offspring will have a more severe food allergy. With two parents, 85% of the offspring will have a more severe food allergy. With controlled exposure to the allergen, the gene expression changes to the non-allergenic state. (I received this treatment with injections as a child, and have not had any food allergies since.) An open research question – will this epigenetic change to the non-allergic state be heritable?

• Athena Aktipis’s tantalizing comparisons of conserved evolutionary homologs in cancer and microbial consortia. “Tumor growth is less of a problem than metastases spreading throughout the body and deregulating various systems. The mechanism of death is not really known in cancer research.” “All cells are connected to their neighbors, and then they disperse. When their consumption rate becomes a resource limitation, they follow a gradient to greater resources.” (this sounded exactly like a description of E.Coli, which I marveled at on this earlier post). Given the convergent evolution across many information networks (from genes to protein kinase cascades, to neurons), I had to ask about Bonnie Bassler’s work hijacking the quorum sensing communication channels between bacteria — not to kill the bacteria, which induces evolutionary resistance — but to fool them with “counter intelligence” signaling so they happily live on without flipping into virulent mode. “Yes,” she said “To treat cancer, we could resolve the resource dilemma at the cellular level and, paradoxically, feed the tumor. Our goal should be to prolong life, not kill cancer.”