A gene that regulates bone growth and muscle metabolism in mammals may take on an additional role as a promoter of brain maturation, cognition and learning in human and nonhuman primates, according to a new study led by neurobiologists at Harvard Medical School.
Describing their findings in the Nov. 10 issue of Nature, researchers say their work provides a dramatic illustration of evolutionary economizing and creative gene retooling — mechanisms that contribute to the vast variability across species that share nearly identical set of genes yet differ profoundly in their physiology.
For their experiments, the team analyzed RNA levels — the molecular footprints of gene activity — in the brain cells of mice, rats and humans. Although many of the same genes were activated in both mouse and human brain cells, the scientists observed, a small subset of genes was activated solely in human brain cells. Much to the scientists’ surprise, the bone gene osteocrin was most highly expressed in the human brain, yet completely shut off in the brain cells of mice.
In short, the same genes are doing “profoundly” different jobs in humans than in mice.
The gene’s marked presence in an area of the brain responsible for higher-level function and thought, the researchers said, suggests a possible role in the development of cognition, a cardinal feature that distinguishes the brains of human and nonhuman primates from those of other mammals.
Furthermore, the team added, this is the first illustration of evolutionary gene repurposing the brain.
Repurposing? Wasn’t the whole point of Darwinism to throw purpose out of science? These people may need a Terminology Intervention. Guys, it needn’t make sense; it just needs to be Darwin.
“We have uncovered what we believe is a critical clue into the evolution of the human brain, one that gives us a glimpse into the genetic mechanisms that may account for differences in cognition between mice and humans,” said senior investigator Michael Greenberg, the Nathan Marsh Pusey Professor of Neurobiology and chair of the HMS Department of Neurobiology. Paper. (paywall) – Bulent Ataman et al., Evolution of Osteocrin as an activity-regulated factor in the primate brain. Nature, 2016; 539 (7628): 242 DOI: 10.1038/nature20111. More.
Of course, if the gene really worked in any naturalist way, it should have had the same effect in mice and rats rather than accidentally leading to consciousness.
See also: New tree of life challenges vertebrate evolution: If evolution takes place by a number of means other than Darwinian descent, as now seems the case, the whole concept of a tree of life is passé. That doesn’t mean it’ll die out; only that it will confuse people.
Cichlid speciation attributed to “plasticity” now : What’s interesting about this account is the relatively relaxed (thus more correct) attitude to speciation, an oblique sign of weakening Darwinism. Darwinism depends on the concept of speciation. When speciation just isn’t very clear, Darwinism just isn’t very clear.
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