Excerpt: “… humans have fixed mutations that yield two amino acid substitutions in comparison with other primates…’
My comment: Amino acid substitutions are nutrient-dependent and pheromone-controlled. The idea that the amino acid substitutions are due to mutations is one of the confusing left-overs from the ridiculous theory of mutation-initiated natural selection. For example, people tell me that mutation-driven evolution has occurred in microbes and usually cite the experiments of Richard Lenski as proof. But you don’t prove that anything mutated via changes in antibiotic resistance, or by demonstrating ecological adaptation when the organism survives on a different nutrient source. That’s what was shown in this experiment: Real-Time Evolution of New Genes by Innovation, Amplification, and Divergence .
Nutrient-driven gene duplication resulted in nutrient-driven differentiation of cell types that occurred via alternative splicings of pre-mRNA and amino acid substitutions that stabilized organism-level thermoregulation, which is controlled by the physiology of reproduction. Unfortunately, these researchers reported their results in terms of mutation-initiated natural selection.
Other researchers continue to repeatedly make the same misrepresentations of cause and effect. For example, in vertebrates the single amino acid substitution of achiral glycine in the gonadotropin releasing hormone molecule is the source of nutrient-dependent thermodynamic stability associated with the pheromone-controlled physiology of reproduction across what appears to be approximately 400 million years of vertebrate evolution. Perhaps that is why researchers finally checked to see if mutations were fixed in the genome of the model organism C. elegans.
An experimental test on the probability of extinction of new genetic variants revealed that “…genetic diversity could be maintained indefinitely, without one allele or the other ever being fixed in the population.” Thus, there is no reason for any mutation to be fixed in the DNA of any organized genome in any species from microbes to man. Besides, mutations tend to be removed because they perturb cell type thermoregulation. For contrast, ecological adaptations require fixation of alleles that benefit epistasis via consistency in nutrient-dependent thermodynamics of intercellular signaling that result in organism-level thermoregulation.
Ecological adaptations are much less likely if a mutation is fixed, which is why no experimental evidence ever suggested that mutations are fixed. See also: Extended brain functions would have driven rapid and drastic changes in the hominin ecological niche, which in turn demanded further brain resources to adapt to it. In this way, humans have constructed a novel niche in each of the ecological, cognitive and neural domains, whose interactions accelerated their individual evolution through a process of triadic niche construction. Had these authors included social niche construction, the result might have been quadratic niche construction, which is how ecological adaptations result in species diversification and increasing organismal complexity, which is attributed to “tool use” in their model.