October 15, 2013 | James Kohl
Chemical informatics: Sense of achievement Published October 15, 2013
Excerpts: “Only a few, very important odorants—such as pheromones (Nakagawa et al., 2005) or the odorants given off by rotten food (Stensmyr et al., 2012)—have a one-to-one relationship with specific olfactory receptors.”
“Now, in eLife, Sean Boyle, Shane McInally and Anandasankar Ray of the University of California at Riverside describe a new method that can predict which odorants interact with which receptors much more accurately than previous methods (Boyle et al., 2013).”
Expanding the olfactory code by in silico decoding of odor-receptor chemical space Published October 1, 2013
Excerpts: “Each volatile chemical in the environment is thought to interact with a specific subset of odorant receptors depending upon odor structure and binding sites on the receptor. This precise detection and coding of odors by the peripheral olfactory neurons are subsequently processed, transformed and integrated in the central nervous system to generate specific behavioral responses that are critical for survival such as finding food, finding mates, avoiding predators etc (van der Goes van Naters and Carlson, 2006).”
“This cheminformatics pipeline can also be applied for system-level analysis of other insects whose receptors and ORNs have been decoded such as mosquitoes (Carey et al., 2010), and vertebrates such as mice and humans (Saito et al., 2009).”
My comment: No experimental evidence suggests that this “cheminformatics pipeline” results from mutation-initiated natural selection. Yet this “pipeline” clearly links the epigenetic landscape to the physical landscape of DNA in the organized genomes of invertebrates and vertebrates (e.g., insects, mice, and humans) via olfactory/pheromonal input and the de novo creation of olfactory receptor genes. Where did the idea come from that these olfactory receptor genes are mutated copies of other genes (as Carl Zimmer suggests below)?
Carl Zimmer wrote: “Mammals, for example, smell by binding odor molecules to receptors on nerve endings in their nose. These receptor genes have repeatedly duplicated over millions of years. The new copies mutate, allowing mammals to smell a wider range of aromas.”
Until researchers and science journalists dispense with the idea that mutations cause evolution, scientific progress will be retarded by ignorance of experimentally established biological facts. See for example: Nutrient-dependent/pheromone-controlled adaptive evolution: a model. Socioaffective Neuroscience & Psychology 2013, 3: 20553. The model includes examples of how a nutrient-dependent change in a single base pair results in an amino acid substitution that clearly links adaptive evolution, which has occurred during the past ~30,000 years in a human population in what is now central China, to the same molecular mechanisms of adaptive evolution in mice, other mammals, insects, nematodes, and microbes.