Strong genetic selection against some psych disorders. 1/5/2013 in Psychology & Psychiatry
Excerpt: “Our results suggest that strong selection exists against schizophrenia, autism, and anorexia nervosa and that these variants may be maintained by new mutations or an as-yet unknown mechanism,” the authors write. “Vulnerability to depression, and perhaps substance abuse, may be preserved by balancing selection, suggesting the involvement of common genetic variants in ways that depend on other genes and on environment.”
My comment: Natural selection for food and the metabolism of nutrient chemicals to species-specific pheromones that control reproduction enables adaptive evolution via ecological, social, neurogenic, and socio-cognitive niche construction. New mutations, which are associated with the cause of mental and physical disorders, are not adaptive. That is why there is strong selection against mutations that cause schizophrenia, autism, and anorexia nervosa (see above). It is reduced fecundity that typically selects against mutations in all species that sexually reproduce.
One way to facilitate species divergence in evolved species that sexually reproduce is through balancing selection for common genetic variants that are manifested in phenotype due to existing genetic diversity and the epigenetic effects of nutrient chemicals and pheromones. Thus, it appears to be the balance between nutrition, which is associated with food odors, and socialization, which is associated with pheromones that is responsible for adaptive evolution of different phenotypes.
Epigenetic effects of food odors and pheromones on existing genes in cells and in tissue containing different cell types causes the de novo (new) gene expression that is required for adaptive evolution. Balancing selection (e.g., the balance between food availability and pheromones) promotes survival of cells containing new genes in tissues of organs in organ systems like the central nervous system, which is controlled by hormone-secreting cells in brain tissue.
What you or your mother eats promotes or retards the expression of new genes during development of hormone-secreting brain tissue. Her interactions with conspecifics or your interactions with conspecifics also promotes or retards development of brain tissue via exposure to pheromones that alter hormone secretion. If your brain tissue has adaptively evolved during your prenatal and postnatal development, you will probably reproduce.
If you do not reproduce, that does not mean you are not adaptively evolved. It does not mean you have genetic mutations and are diseased. What the ability to reproduce (or not) means to species survival, which is dependent on food and pheromones, is that balancing selection has ensured the genetic diversity required to respond to an ever-changing epigenetic landscape with changes in the physical landscape of the species’ DNA.
The DNA of every organism in the world that has ever existed has been epigenetically effected by nutrient chemicals and pheromones. Until the details of some as-yet unknown mechanism are offered to us for consideration, it is the epigenetic effects of nutrient chemicals and pheromones on behaviors associated with the development of food preferences and sexual preferences that are responsible for human diversity.
In that context, if someone tries to tell you that others who are not like them are mutants or diseased, look at them and laugh. Similarly, if an evolutionary theorist or philosopher tries to tell you that mutations cause adaptive evolution, look at them and say “You fool!”
I’ve had enough of such foolishness, haven’t you? Who do these people think they are? Why are they so willing to tell us stories about the adaptive evolution of our brain and behavior via mutations? What is it that they want us to believe about the sexual orientation of other people or sexual orientation in species from microbes to man? Why don’t they simply state their beliefs and provide evidence for a model that supports their theories — a model for adaptive evolution, for example, that is not nutrient chemical-dependent and pheromone-controlled?