Study: How likes, dislikes from sniffing are encoded in the brain. January 16th, 2014
Excerpt: “…the aversion is innate-it’s not learned-and that it involves genetic circuits that are genetically predetermined, that exist, dormant, in the animal waiting for it to encounter the odor.”
Journal article abstract excerpt: This smell is mainly carried by two small aliphatic diamines, putrescine and cadaverine, which are generated by bacterial decarboxylation of the basic amino acids ornithine and lysine. Depending on the species, these diamines may also serve as feeding attractants, oviposition attractants, or social cues.
My comment: In my model, nutrient-dependent pheromone-controlled alternative splicings of pre-mRNA and amino acid substitutions lead to the chromosomal rearrangements associated with species-specific morphology and behavior. The amino acid substitutions stabilize the thermodynamics of intercellular signaling and organism-level thermoregulation.
Bacterial decarboxylation of any nutrient-dependent pheromone-controlled amino acid substitutions that enable species-wide epistasis would be a likely indicator that smells like death to a conspecific and a likely indicator of a potential food source to a heterospecific. The transition from a species-specific chemical signal of fitness to a signal associated with impending death or bacterial decomposition would help different species establish and maintain their ecological niche.