Friday, September 9

this brain under construction

I have a new article out in New Scientist (my first for them!).
Human brains enjoy ongoing evolution

The human brain may still be evolving, new research suggests. New variants of two genes that control brain development have swept through much of the human population during the last several thousand years, biologists have found.

Read it here.

I thought perhaps my article overstates the case: an interesting idea, yes, but not much is known about how these genes work and whether natural selection is still at this moment in action, let alone what advantage the new versions of the genes would give people. But clearly some reporters went overboard, like with this headline, from "Human Brains Are Getting Larger, More Complex, Scientists Say." They said nothing like this. Even if our brains are still evolving, they haven't gotten noticeably bigger in in the last 200,000 years. This reporter was obviously grasping at straws.

Anthropologist John Hawks, who I quoted in my article and who works with the researchers who did the genetic studies, has a great blog post where he comments on new studies. He mentions (at the end of the post) how some scientists are careful to point out that the study does not prove what advantage these new gene variants give:
Mark Stoneking in Science:
"The case for selection acting on [the genes] is reasonably strong," says anthropologist Mark Stoneking of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. "However, there is absolutely nothing in either paper to relate the signature of selection to any brain-related phenotype."
But some go too far:
David Goldstein in the New York Times -- my candidate for the "not even wrong" award:
Another geneticist, David Goldstein of Duke University, said the new results were interesting but that "it is a real stretch to argue for example that microcephalin is under selection and that that selection must be related to brain size or cognitive function."

The gene could have risen to prominence through a random process known as genetic drift, Dr. Goldstein said.
I have to say, someone who seriously thinks that these alleles are drift must not believe in natural selection under any circumstances. But possibly Goldstein was misquoted, or may not have seen the papers before making this comment.

So perhaps I'm somewhere in the happy middle after all.

UPDATE: I found a site that posted a press release on this research, and where people posted all manner of comments on it, ranging from intelligent design supporters attacking the studies to amateur philosophers of science defending the scientific method. It's scary for me as a journalist to see how varied people's understanding of something we write can be. I only hope that the people who feel inclined to post are the extremists. But this particular site is supposed to collect "news channels for medical professionals." So perhaps there's no hope.... Link.

And by the way, my housemate Esther asked me what I was working on last week and I said an article on the evolution of the human brain. She said, "You mean the intelligent design of the human brain? I'm from Kansas." But she did it in a deadpan way which—even though it's the way I joke—always catches me off-guard. But joking she was.


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