Random mutations theory and pervasive mosaic evolution (the brain)
December 20, 2012 | James Kohl
Genomic ‘hotspots’ offer clues to causes of autism, other disorders December 20, 2012 in Genetics
Excerpt: “random” mutations in the genome are not quite so random after all.
Michaelson et al.: “Whole Genome Sequencing in Autism Identifies Hotspots for De Novo Germline Mutation.”
My comment: This fits nicely with the claim that the past 5,000 years has been most prolific for changes to human genome. It does not fit with any theory that mutations cause adaptive evolution of the human brain, body, or behavior. Mutations, for example, typically cause deleterious effects. The effects in autism on social behavior are clear. They are even more clear in the context of nutrient chemical-dependent pheromone-controlled reproduction which is how adaptive evolution works across other species from microbes to man.
Does anyone truly believe these “mutations” are not simply nutrient chemical-dependent changes via epigenetic effects of food (from the bottom up) and epigenetic effects of pheromones (from the top down) on adaptive evolution of atypical genetically-predisposed brain-directed behaviors? If you believe that, then can you explain why de novo germline mutations vary with genetic sex as they clearly appear to do with incidence rates of autism and autism spectrum disorders?
How does the 86% of deleterious mutations result in our advanced brain development during precisely the same time that dietary change would be expected to do so? Is there a model for that?
As I recall, there’s a theory of evolution via random mutations — or perhaps just “mutations” that are not random, but that ridiculous theory requires revision. Excerpt: “Collectively, these studies suggest that the true mutation rate in humans is lower than previous theoretical estimates by Haldane (2004), Kondrashov and Crow (1993), and Nachman and Crowell (2000), possibly by as much as a factor of two. This knowledge has led some to consider a recalibration of the timescales of human evolution and the divergence of human populations (Scally and Durbin, 2012).” Should we allow the theory to continually be revised as new data on nutrient chemical-dependent pheromone controlled adaptive evolution becomes readily available? Should we refer to mutations as “adaptive mutations?” I think we should collectively decide to recognize adaptive evolution via epigenetic effects of nutrient chemicals and pheromones on ecological, social, neurogenic, and socio-cognitive niche construction for what it is. It’s the only only model for that!
See also for mutation hot spots in microbes: Our work suggests that specific mutation hot spots can contribute disproportionately to the genetic variation that is introduced into populations and provides long-range genomic sequence context that contributes to mutagenesis.