December 8th, 2013
Excerpt: “…the underlying amino acid sequence can vary slightly for each of the 400 receptor proteins, resulting in one or more variants for each of the receptors. Each receptor variant responds to odors in a slightly different way and the variants are distributed across individuals such that nearly everyone has a unique combination of olfactory receptors.”
See: The missense of smell: functional variability in the human odorant receptor repertoire [Subscription required]
Abstract excerpt: “…we verified that variations in OR10G4 genotype explain over 15% of the observed variation in perceived intensity and over 10% of the observed variation in perceived valence…”
Natural selection enables changes in the underlying amino acid sequences of olfactory receptor genes. Natural selection is experience-driven by the availability of nutrients. It is also directly and epigenetically linked from nutrients in the ecological niche to behavior. For example, behavioral differences linked to epigenetically-effected massive neural circuit rewiring between a microbivore and a predatory nematode have been attributed to an evolutionary novelty unknown in their most recent common ancestor. “P. pacificus and its relatives develop teeth-like denticles in their mouth opening and can form two distinct mouth forms (Bumbarger et al., 2013 – p 109).”
Physical evidence of this evolutionary novelty exemplifies three different aspects of de novo creation:
1) de novo creation of olfactory receptor genes that enable nutrient uptake and
2) de novo creation of species-specific pheromones via the metabolism of nutrients and
3) de novo creation of the first “teeth.”
Thus, the de novo creation of teeth is adaptive in the context of biophysically constrained nutrient-dependent physiology of reproduction, which is controlled by species-specific pheromones.
For contrast, some people still believe “natural selection” is an evolutionary process initiated by mutation that does not have any creative power (see Nei: Mutation-driven evolution, page 196). However, additional physical evidence of de novo creation that links nutrient uptake to amino acid substitutions and pheromone-controlled reproduction which enable species to construct ecological, social, neurogenic, and socio-cognitive niches, can be found with increasing organismal complexity. (See for review: Nutrient-dependent/pheromone-controlled adaptive evolution: a model.)
No experimental evidence suggests that mutation-initiated “natural selection” links the epigenetic landscape to the physical landscape of DNA in the organized genome of any species. Thus, there is obviously no such thing as mutation-driven evolution. Instead, in species from nematodes to whales nutrient-dependent pheromone-controlled “…differences in amino acid composition among different tissues can lead to large differences in trophic discrimination .” These differences are associated with visually perceived differences in phenotype that are caused by biophysically constrained conserved molecular mechanisms in species from microbes to man.
Nevertheless, a review of more than 750 blog posts found here will confirm that no matter how much scientific evidence refutes the theory of mutation-driven evolution, that theory will continue to be taught to students by professors who are unwilling to accept a new scientific truth. The truth is: the theory of mutation-driven evolution does not make sense; it never did.