Science 12 July 2013:
Vol. 341 no. 6142 p. 118
DOI: 10.1126/science.341.6142.118
EVOLUTION
Field Test Shows Selection Works in Mysterious Ways
Elizabeth Pennisi
Excerpt: “Barrett has swept the main awards for young evolutionary biologists, capping off his run last month at the Evolution 2013 meeting with the Dobzhansky Prize from the Society for the Study of Evolution.”
My comment: “… ‘reproductive isolation evidently can arise with little or no morphological differentiation’ (Dobzhansky, 1972, p. 665). That makes sense if nutrients and pheromones are intricately involved. At the same time, some theorists correctly claim that ‘nothing in biology makes any sense in the absence of evolution’ (Dobzhansky, 1973). If Dobzhansky was correct, claims of choice for mutations represented in morphology, which are commonly voiced in the context of random mutations theory, make no sense. For contrast, claims of choice for nutrient-dependent differences in pheromone production have always made sense across the evolutionary continuum of species diversity.” — Kohl (2013)
Excerpt: Researchers have long assumed that the dune mice lightened up to become less visible to airbone predators such as owls…. That tidy tale left Barrett dissatisfied. “This has been one of the longest-standing adaptive stories in evolutionary biology, but the hypothesis that cryptic coloration is adaptive has never been directly tested in deer mice under natural conditions,” he says.
My comment: Cryptic coloration in the peppered moth example of industrial melanism was attributed to random mutations and Natural Selection via predation by birds. However, the 2km per night pattern of color change matched the distance some male moths will fly upwind to find a female that produces the most attractive mixture of nutrient-dependent pheromones.
Industrial pollution contributed to increased lead and manganese on the leaves that moth larvae fed on. Thus, a change in pheromone production could readily be attributed to a change in the diet of the larvae, which experiments showed were responsible for the color change from fawn to peppered and back.
If the color change from fawn to peppered and back were mutation-driven by predatory Natural Selection, the reversal of the color change should be considered in the context of rapid changes not typically attributed to accumulated mutations. For contrast, changes in morphogenesis, including color, are commonly attributed to nutrient-dependent pheromone-controlled adaptive evolution.
Excerpt: “…his preliminary results suggest color does protect the dune mice—but that other genes also help the mice thrive. The results show that “there are other things that played a role in adaptation…”
My comment: “Current concepts now limit attempts to explain selection for nutrient-dependent changes in coat color and kinked tails in mice via mutations theory, since mutations theory does not address pleiotropy and epistasis (see for review Feinberg & Irizarry, 2010). — Kohl (2013)
Excerpt: But many genes not related to pigment also changed over the course of the experiment. The analysis revealed “a potentially large number of genetic regions responding to selection,” Barrett reported. He doesn’t know what traits those changes affect, but he’s investigating each one—and suspects some have nothing to do with surviving predation. They might make a mouse healthier overall, or better able to find food, for example.
My comment: Nutrient-dependent pheromone-controlled adaptive evolution of the immune system make animals heathier and better able to find food, which means they will be more likely to find mates.
Excerpt: “A lot of what we know about selection is very crude,” Schluter says. “When we start to do experiments we are surprised to find stuff happening that we didn’t anticipate.”
My comment: What we can anticipate from the conserved molecular mechanisms in my model of nutrient-dependent pheromone-controlled adaptive evolution is “…an epigenetic effect of nutrients on hormones responsible for the tweaking of immense gene networks that metabolize nutrients to pheromones. The pheromones control the nutrient-dependent hormone-dependent organization and activation of reproductive sexual behavior in mammals such as mice and humans, but also in invertebrates…”
We can also conclude that food odors and pheromones link the honeybee model organism and other invertebrate and vertebrate model organisms to olfaction and odor receptors across species. This link provides ‘… a clear evolutionary trail that can be followed from unicellular organisms to insects to humans’ (Kohl, 2012).” That means color morphs in deer mice also are nutrient-dependent and pheromone-controlled as exemplified in the Ostrinia moth. See: Substitution of a critical amino acid results in a novel pheromone blend.
