There are days when I simply cannot believe how dishonest the scoundrels at the Discovery Institute can be. This is one of them. I just read an essay by Jonathan Wells that is an appalling piece of anti-scientific propaganda, an extremely squirrely twisting of some science news. It’s called “Why Darwinism is doomed”, and trust me, if you read it, your opinion of Wells will drop another notch. And here you thought it was already in the gutter!
First, here’s the science news that was published in Nature back in August, and which has set Wells off. The research is the result of the ability to scan and compare genomic databases. Such searches have identified regions that are conserved in vertebrates, but also exhibit striking differences in humans; these are called Human Accelerated Regions, HARs, and are considered likely hotspots for finding the specific, selected genetic changes that resulted in Homo sapiens‘ unique characters.
One specific candidate gene that was identified by Pollard et al. is called HAR1F. HAR1F has several attributes that make it an interesting focus for research: 1) it’s in a HAR, and it’s changed dramatically between humans and chimpanzees. 2) It’s expressed in the cerebral cortex during development, and seems to be important in regulating interactions between cells that establish the critical layered structure of this region of the brain. And 3) it’s odd, in that it isn’t translated into protein, but the RNA itself affects the action of other genes. Novel mechanisms are always interesting, and it suggests that we should pay more attention to non-coding RNA as a developmental regulator.
They conclude their study with this comment:
Our comparative genomic approach to identify the most dramatically changed segments of DNA in the human genome has identified a number of new candidate regions to test for clues in the attempt to decode the key events in human evolution. The first on this list seems to define a new type of RNA molecule expressed at a very crucial time and place in the development of the neocortex. Many of the other top candidates are associated with genes known to be involved in neurodevelopment, an area where there has been significant divergence since our last common ancestor with chimpanzee. Thus, this seems to be a promising approach to identifying candidate regions involved in neurodevelopmental aspects of our uniquely human biology.
In a short news blurb in Nature, Kerri Smith described it this way:
Researchers have identified a gene that has changed rapidly during human evolution — a discovery that could be a step towards understanding what sets us apart from other animals.
OK, most of you reading this are normal, literate, reasonably intelligent human beings. I can guess what you are thinking: scientists have taken one more tentative step towards understanding the molecular, genetic, and developmental basis of brain organization. Cool! It sure raises a lot of questions, but this is the way science works, by the incremental addition of new information.
If you were Jonathan Wells, though, the antithesis of the kind of people I like to associate with, it prompts a whole succession of bizarre non-sequiturs. “Darwinism is doomed.” “Darwinism is not a scientific theory.” The evidence for evolution is “underwhelming”. It encourages him to conclude,
If I were a Darwinist, I would be afraid. Very afraid.
If I were Jonathan Wells, I would seek medical attention immediately.
By what possible train of erratic logic could Wells have arrived at his strange conclusions? He gives three arguments.
First, it implicitly acknowledges that the evidence for Darwinism was never as overwhelming as its defenders claim. It has been almost 30 years since Gould wrote that biology accounts for human nature, yet Darwinists are just now turning up a gene that may have been involved in brain evolution.
The story acknowledges no such thing. The evidence for evolution of the brain is inarguable, but that does not mean that we know every detail of the mechanism, or that we’re all done figuring out the entire universe. For example, I flew to New York on Monday; if someone there had asked, for instance, what airline I’d used, does their ignorance of every step of my travel somehow cast doubt on the fact that I had gotten from Minnesota to New York? If the details and timing of my itinerary are worked out, does the fact that I don’t remember the number of my parking spot at the Park ‘n’ Fly mean there is cause to question that I’d even made the trip?
Scientists have never claimed to have all the answers to the evolution of the human brain. We have claimed to possess a process that will help us decipher the events leading to our big brains, and this study demonstrates that we have tools and ways to apply them that are bringing us closer, in ways the IDists can’t even dream of.
Which brings up an important question: does the Discovery Institute have the complete recipe for forming a brain? If not, where do they get off complaining that incomplete information is the signature of future doom? Since their information is far smaller in quantity, doesn’t that suggest their demise is even more imminent?
One last point. If the discovery of small bits of information is a sign of failure, this attitude from Wells is rank anti-science—if the IDists were in charge, new knowledge would be regarded as a violation of current dogma. Let’s make sure these clowns never have any influence on science or policy.
His remaining two arguments move from the anti-scientific stupidity of his first, to patent straw man thrashing.
Second, embryologists know that a single gene cannot account for the origin of the human brain. Genes involved in embryo development typically have multiple effects, and complex organs such as the brain are influenced by many genes. The simple-mindedness of the “brain evolution gene” story is breathtaking.
Read the papers. You will not find a single statement to the effect that this is a single gene that accounts for the origin of the human brain. They discuss other genes, such as reelin, with which HAR1F is thought to interact; they talk about a possible interfering RNA, HAR1R, that modulates its expression; they discuss expression of the gene in other tissues, like testis. The only thing simple-minded here is Wells’ misleading caricature of the paper.
Third, the only thing scientists demonstrated in this case was a correlation between a genetic difference and brain size. Every scientist knows, however, that correlation is not the same as causation. Among elementary school children, reading ability is correlated with shoe size, but this is because young schoolchildren with small feet have not yet learned to read — not because larger feet cause a student to read better or because reading makes the feet grow. Similarly, a genetic difference between humans and chimps cannot tell us anything about what caused differences in their brains unless we know what the gene actually does. In this case, as Nature reports, “what the gene does is a mystery.”
Again, the paper talks about this very issue in depth. They have analyses that show signs of selection for variations in the gene; they have patterns of expression in the brain; they have potential interactions laid out; they specifically state that there are good questions to ask about the specific function of HAR1F. They do not claim to have a known causal relationship. They’ve got a promising research program (which the IDists obviously lack).
Yes, we would like to know much more about what the gene does. Unfortunately, when we do learn a little more, I’m sure Wells will be there to prognosticate the demise of Darwinism because, doggoneit, those scientists keep learning new things, proving that they didn’t know everything.
Ares M Jr,
Haussler D. (2006) An RNA gene expressed during cortical development evolved rapidly in humans. Nature 443(7108):167-72.
Smith K (2006) Homing in on the genes for humanity. Nature 442:725.