Granpappy was a Neandertal

Fascinating stuff…read this paper in PNAS, Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage, or this short summary, or John Hawks’ excellent explanation of the concepts, it’s all good. It’s strong evidence for selection in human ancestry for a gene, and just to make it especially provocative, it’s all about a gene known to be involved in brain growth, and it’s also showing evidence for interbreeding between Homo sapiens and Neandertal man.

The short short explanation: a population genetics study of a gene called microcephalin shows that a) it arose and spread through human populations starting about 37,000 years ago, b) this particular form of the gene (well, a small cluster of genes in a particular neighborhood) arose approximately 1.1 million years ago in a lineage distinct from that of modern humans, and c) the likeliest explanation for this difference is that that distinct lineage interbred with modern humans 37,000 years ago, passing on this particular gene variant that was then specifically selected for, a process called introgression.

The work looks sound to me, and I’m convinced. The one thing to watch for, though, is that there will be attempts to overreach and couple possession of this gene to some kind of intellectual superiority. We don’t know what this particular variant of the gene does yet! All we can say at this point is that some abstract data shows that a particular allele spread through the human population at a rate greater than chance would predict, that the gene itself has as one of its functions the regulation of brain growth, but that it is highly unlikely that that particular function is affected by the variant. Whatever it does, I expect the role is more along the lines of subtle fine-tuning rather than simply making people smart.

Hands off those genes

Here’s an annoying case of political correctness run amuck.

…the Human Genome Organisation (HUGO) Gene Nomenclature Committee…is renaming a number of genes that have potentially offensive or embarrassing names.

The shortlist of 10 genes - including radical fringe, lunatic fringe and, bizarrely, Indian hedgehog – was compiled in response to physicians’ worries about “inappropriate, demeaning and pejorative” names.

The problem arose because most of the genes were initially discovered in fruitflies, and their names were then transferred to the human versions of the genes, which were discovered later…when applied to the human versions of the genes, many of these names become uncomfortable.

While no one wants to curtail the creativity of fruitfly geneticists, it will be important to ensure that, in the future, no joky names are adopted for human genes where they might cause offence. Other quirky names in the fruitfly genome include headcase and mothers against decapentaplegia (MAD).

Darn prissy physicians. They’ve got no sense of humor. Will they try to rename one-eyed pinhead next? How about half baked? The zebrafish geneticists are just as amusing, you know.

I’d like to know what the physicians are concerned about, anyway. It’s not as if they’re going to be informing patients that their illness is caused by a broken frizzled gene, nor is it going to be somehow better or easier if they rename it “Wnt Receptor X-17” or something similarly dry and empty. I hope whoever started this knows a good proctologist who can do a stick-ectomy.

And seriously, there ought to be something like the priority rules of taxonomy to prevent random gomers from running around changing names just because they don’t like them.

Feminism is undermining human evolution!

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Human X (left) and Y (right) chromosomes

Did the internet get stupider while I was away this past week? I mean, it’s gratifying to my ego to imagine the average IQ of the virtual collective plummeting when I take some time off, but I really can’t believe I personally have this much influence. Maybe the kooks crept out in my absence, or maybe it was just the accumulation of a week’s worth of insanity that I saw in one painful blort when I was catching up.

What triggers such cynicism is the combination of Deepak Chopra, Oliver Curry, and now,
William Tucker. Tucker wrote a remarkably silly piece in the American Spectator in which he drew deeply faulty conclusions from human genetics to support a thesis rife with misogyny and foolish chauvinism on human evolution. It was like a piece on evolutionary psychology written by someone who didn’t know any genetics at all.

Hang on to your hats—we’re going to see a factoid from one magazine article balloon up into a declaration of the superiority of the male species (I use “species” here both ironically and mockingly).

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SciAm explains hothead

You may have heard about that odd hothead mutation in Arabidopsis that seemed to be violating a few principles of basic genetics—there was an unexpectedly high frequency of revertants that suggested there might be a reservoir of conserved genetic information outside the genome. Reed Cartwright proposed an alternative explanation, that gamete selection could skew the results. Now the latest reports suggest that the bias was an artifact of foreign pollenization (which I think is interesting in itself. Life is damned good at sneaking its genes in wherever it can.)

Anyway, if that’s all gobbledygook to you, Scientific American has put up a lucid summary of the hothead affair. It’s an example of good science, where the observations and hypotheses are hammered out and refined to get a best explanation.

How would ID have contributed?

Carl Zimmer brings up another essential point about the HAR1F study: it was work that was guided by evolutionary theory. The sequence would not have been recognized in the billions of nucleotides in the genome if it hadn’t been for an analysis directed by the principles of evolution.

Wells’ diatribe was amazingly wrong. I looked at it again and there could be another half-dozen essays in just picking up apart the stupidity in it.

What works, what doesn’t: the futility of appeasing creationists

An old pal of mine, the splendiferously morphogenetical Don Kane, has brought to my attention a curious juxtaposition. It’s two articles from the old, old days, both published in Nature in 1981, both relevant to my current interests, but each reflecting different outcomes. One is on zebrafish, the other on creationism.

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Luskin’s ludicrous genetics

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I mentioned before that IDEA clubs insist that expertise is optional; well, it’s clear that that is definitely true. Casey Luskin, the IDEA club coordinator and president, has written an utterly awful article “rebutting” part of Ken Miller’s testimony in the Dover trial. It is embarrassingly bad, a piece of dreck written by a lawyer that demonstrates that he knows nothing at all about genetics, evolution, biology, or basic logic. I’ll explain a few of his misconceptions about genetics, errors in the reproductive consequences of individuals with Robertsonian fusions, and how he has completely misrepresented the significance of the ape:human chromosome comparisons.

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Carnivalia, and an open thread

We just had one of these!

Well, just to flesh it out a little more with some random links, here are some photos. I was told the second one made someone think of me (warning: body modification!). And, jebus help me, for some reason I thought this photo was very sexy. Or appetizing. I don’t know, something in the midbrain flickered.

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Oh, and several of us sciencebloggers were interviewed for an article by Eva Amsen on “Who benefits from science blogging?” It doesn’t mention the benefit of people sending you pictures that tickle the cingulate.

Patterning the nervous system with Bmp

I’m a little surprised at the convergence of interest in this news report of a conserved mechanism of organizing the nervous system—I’ve gotten a half-dozen requests to explain what it all means. Is there a rising consciousness about evo-devo issues? What’s caused the sudden focus on this one paper?

It doesn’t really matter, I suppose. It’s an interesting observation about how both arthropods and vertebrates seem to partition regions along the dorso-ventral axis of the nervous system using exactly the same set of molecules, a remarkable degree of similarity that supports the idea of a common origin. Gradients of a molecule called Bmp may be the primitive mechanism for establishing dorso-ventral polarity in animals.

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