Excerpt: “…the direct contribution of ecological divergence to speciation is uncertain, in part because relatively few systems have been investigated experimentally, and the genes affecting dual traits have not been identified.”
My comment to Science Magazine (submitted Fri Feb 14, 2014 at 4:06 AM; published Tuesday, Feb 18, 2014 at 12:28 pm)
“In flies, ecological and social niche construction can be linked to molecular-level cause and effect at the cellular and organismal levels via nutrient-dependent changes in mitochondrial tRNA and a nuclear-encoded tRNA synthetase. The enzyme enables attachment of an appropriate amino acid, which facilitates the reaction required for efficient and accurate protein synthesis (Meiklejohn et al., 2013).” — Kohl (2013) Nutrient-dependent pheromone-controlled adaptive evolution: a model.
Chung et al (2014) extend the concept of nutrient-dependent pheromone-controlled epigenetically-effected alternative splicings of pre-mRNA from our section on molecular epigenetics in a 1996 Hormones and Behavior review article. Elekonich and Robinson (2000) already did that for insects before Elekonich and Roberts (2005) used the conserved molecular mechanisms approach in an extension to “Honey bees as a model for understanding mechanisms of life history transitions.”
Someone else may help others to understand the experimental evidence from this study in the context of mutation-initiated natural selection, if it does not fully support the paradigm shift to a model of ecological variation, natural selection for food, and metabolism of nutrients to species-specific pheromones that control the physiology of reproduction.
However, in the context of ecological adaptations I think this experimental evidence establishes the fact that “Olfaction and odor receptors provide a clear evolutionary trail that can be followed from unicellular organisms to insects to humans.” Kohl (2012)
For comparison of cause and effect in the current report co-authored by Sean B. Carroll to his historical representations see:
— and Carroll, S.B. (2008) The regulation and evolution of a genetic switch controlling sexually dimorphic traits in Drosophila.
Excerpt: “The properties of these CREs resolve the question of how the effects of mutations can be restricted to one sex.”
My summary: One of the two sexes must have mutated into existence.
For a comparison to my historical perspective on ecological adaptations, which was co-authored by a researcher with my surname, see also:
Kohl, Johannes. et al. (2013) A Bidirectional Circuit Switch Reroutes Pheromone Signals in Male and Female Brains.
Excerpt 1): “This bidirectional switch, analogous to an electrical changeover switch, provides a simple circuit logic to activate different behaviors in males and females.”
Excerpt 2): “This model appears directly applicable to sex-specific processing of mouse pheromones…”
Excerpt 3): “…cVA and food odors could interact in a supralinear way to promote female courtship or egg laying. This parallels the convergence in the lateral horn of a labeled line responsive to non-cVA fly odors (Or47b/VA1lm neurons) and one responsive to a specific food odorant, phenylacetic acid, that acts as a male aphrodisiac…”
My summary: Conserved molecular mechanisms lead from nutrient-dependent pheromone-controlled sexual differentiation in yeasts to mammals.
My comment: Both articles were published in the same prestigious journal. In 2013, the conserved molecular mechanisms of nutrient-dependent pheromone-controlled monogenic ecological divergence via sexual differentiation in my model were extended by Johannes Kohl to the nutrient-dependent pheromone-controlled switch that Sean B. Carroll and many others still seem to believe evolved via an ecologically altered mutation that led to sex differences and to species differences in morphology and behavior.
If monogenic ecological divergence is mutation-driven in flies, the explanation of how mutations cause ecological divergence will be interesting to see. The explanation will no doubt fly in the face and be as irritating as a fly up the nose of anyone who is familiar with what is currently known about how the singularity of epigenetically-effected de novo monoallelic creation and expression of olfactory receptor genes links the epigenetic landscape to the physical landscape of DNA in the organized genomes of species from microbes to man.