Neanderthal ancestry drives evolution of lipid catabolism in contemporary Europeans
Excerpt 1) “It is appealing to speculate that genetic variants affecting lipid catabolism in modern Europeans were acquired by modern human ancestors through genetic flow from Neanderthals, and then spread rapidly though the ancestral population by means of positive selection.”
Excerpt 2) “If the lipid catabolism gene variants we find in Neanderthals and contemporary Europeans were already present in the ancestors of Neanderthals and out-of-Africa human populations, they may have independently increased in frequency in Neanderthals and humans situated in the European region. This scenario is probable if these genetic variants provided an adaptive advantage to both Neanderthal and human populations in the conditions of prehistoric Europe. While the presence of a recent positive selection signal in lipid catabolism gene variants containing NLS in modern Europeans supports such an adaptive scenario, the environmental pressures or functional mechanisms of this possible adaptive change remain elusive.”
My comment:
Excerpt 1) is biologically implausible speculation with no explanatory power. It is akin to what is typically discussed in terms of mutations and natural selection, which appears to occur only in the context of population genetics. For example, beneficial mutations must somehow supposedly result in natural selection for morphological and behavioral phenotypes that appear to result in increasing organismal complexity and species diversity.
Excerpt 2) includes what is currently known about biophysical constraints on protein folding that ensure the metabolism of nutrients to species-specific pheromones controls the physiology of reproduction, which enables sexual selection for nutrient-dependent sex differences in pheromones. There is a model for that!
See, for example: Nutrient-dependent/pheromone-controlled adaptive evolution: a model. Experimental evidence now supports a revised view of adaptive evolution, because only ecological adaptations have been exemplified. See, if published: Nutrient-dependent pheromone-controlled ecological adaptations: from atoms to ecosystems (under review). While you wait, see Nutrient-dependent / Pheromone-controlled adaptive evolution: (a mammalian model of thermodynamics and organism-level thermoregulation).
See also: Genes without prominence: a reappraisal of the foundations of biology. It details aspects of biophysical constraints on protein folding and ecological adaptations that eliminate theories associated with mutations and evolution. Ecological adaptations result in species diversity, constraint-breaking mutations do not.
See also: A quantum theory for the irreplaceable role of docosahexaenoic acid in neural cell signalling throughout evolution. Linking any nutrient to ‘evolution’ is a misrepresentation of the physics, chemistry, and conserved molecular mechanisms that enable ecological variation to result in ecological adaptations in species from microbes to man. Inaccurate claims of evolution can now be viewed in the light of accurate claims that ecological adaptations have occurred.
However, Neanderthal ancestry drives evolution of lipid catabolism in contemporary Europeans was reported as:
An Ancient Evolutionary Advantage?
Shared sequences within the brain lipid-metabolism pathway between Neanderthals and modern Europeans highlight questions about how these genetic similarities arose.
By Emily Willingham | April 1, 2014
Excerpt: “… what drove the adaptive selection for these lipid metabolism-associated gene variants remains unknown. “At this point, we cannot directly link these changes and environmental effects,” Lachmann said. He added that the human brain exists in state of “relatively constant” metabolic inputs and outputs, so what happens in the head isn’t simply a matter of direct influence from external factors.”
Food odors and pheromones directly link the epigenetic landscape to the physical landscape of DNA in the organized genomes of all species. What happens in the head is clearly nutrient-dependent and pheromone-controlled because it is a manifestation of ecological, social, neurogenic, and socio-cognitive niche construction. For example, nutrient-dependent single nucleotide polymorphisms and amino acid substitutions differentiate cell types in individuals of all species. Pheromones control the physiology of nutrient-dependent reproduction, which is epigenetically-effected by nutrient stress and social stress during brain development. See for example: Mosaic Copy Number Variation in Human Neurons. ” One straightforward hypothesis is that neurons with different genomes will have distinct molecular phenotypes because of altered transcriptional or epigenetic landscapes.”
That hypothesis, which I have modeled, is more fully supported by works co-authored by Philipp Khaitovich, the senior author of Neanderthal ancestry drives evolution of lipid catabolism in contemporary Europeans.
