Last week, I described the lectures I attended at the Chicago 2009 Darwin meetings (Science Life also blogged the event). Two of the talks that were highlights of the meeting for me were the discussions of stickleback evolution by David Kingsley and oldfield mouse evolution by Hopi Hoekstra — seriously, if I were half my age right now, I’d be knocking on their doors, asking if they had room for a grad student or post-doc or bottle-washer. They are using modern techniques in genetics and molecular biology to look at variation in natural populations in the wild, and working out the precise genetic changes that led to the evolution of differences in development and morphology. They are doing stuff that, back when I actually was a graduate student, would have been regarded as technically impossible; you needed model systems in the laboratory to have the depth of molecular information required to track down the molecular basis of novel morphs, and you couldn’t possibly just grab some interesting but otherwise unknown species out on a beach or a pond and work out a map and localize genetic differences between individuals. They’re doing it now, though, and making it look easy.
Then there were all the other talks in population genetics and paleontology (and the talks on history and philosophy, which I almost entirely neglected)…this was a meeting that everywhere demonstrated major advances in our understanding of evolution. Every talk was about the successes of evolutionary theory and directions to take to overcome incomplete areas of understanding; this was a wonderfully positive and promising event that should have impressed all the attendees with the quality of the work that has been done and the excitement of the potential for future research. Like I said, there were a whole bunch of people here that I want to be when I grow up.
Well, normal people would feel that way. Paul Nelson, that creationist, was also there. Nelson is a weird guy; he’s always hanging around the edges of these scientific meetings, and you’d think that after all these years of lurking, he’d actually learn something, but no…the only skill he has mastered is the art of ignoring what he doesn’t like and incorporating fragments of sentences into his armor of ignorance. It’s very sad.
I talked with Nelson briefly at a reception at the meetings, and we both agreed on the quality of Kingsley’s work — but that’s about all. Nelson thought it supported ID better than neo-Darwinian evolutionary theory. His argument was that a) all anybody ever described was loss of features, and b) a large parent population was the source of all the allelic variation in the sub-populations studied, which is what ID predicts. He didn’t mention their favorite magic word of “front-loading”, but I could see what he was thinking.
How Nelson can hang about on the fringes of the evo-devo world and not notice that what was described by modern empirical research is exactly what the evo-devo theoreticians expected is a mystery — these were results that fit beautifully what science, not the wishful voodoo of intelligent design creationism, predicts.
Both Kingsley and Hoekstra are looking at recent species, subpopulations that separated from parent populations within the last ten thousand years, and have adapted relatively rapidly to new environmental conditions. The sticklebacks are fragments of marine species that were isolated in freshwater streams and lakes, while the beach mice are parts of a widespread population of oldfield mice that are adapting to gulf coast islands. They are also working with populations that can be bred back to the root stock, that retain the ability to do genetic crosses, so of course the variation is not on the magnitude of turning fins into limbs (we need large amounts of geological time to do that; it’s the kind of work Neil Shubin would do, and unfortunately, he can’t cross Tiktaalik with Acanthostega). Complaining that the variants the real scientists are looking at aren’t the kind that the creationists want is a particularly clueless kind of whine, since the scientists are intentionally focusing on the variants that are amenable to dissection by their techniques.
The other aspect of their work that confirms evo-devo expectations is that what they’re discovering is that the genetic mechanisms behind morphological variants are changes in regulatory DNA — that what’s happening is that regulatory genes like Pitx1 or Mc1r are being switched off or on. We anticipate that a lot of morphological novelty is going to be generated by switching genes off and on, and by recombination of patterns of gene expression. Nelson and Behe are reduced to carping on the sidelines that observed variants are just the product of getting large effects by trivially flipping switches, while all the real biologists are out there in the middle of the work happily announcing that we can get large-scale morphological effects by simply flipping switches, and hey, isn’t that cool, and doesn’t that tell us a lot about the origins of evolutionary novelties? It’s not just a to-may-to/to-mah-to difference in interpretation, this is a case of the creationists wilfully and ignorantly missing the whole point of an exciting line of research.
There’s also a fundamental failure of comprehension. Creationists see loss of a feature like pelvic spines, or a reduction in pigmentation, and declare that the evolutionary evidence is “all breaking things and losing things”. Wrong. What we have here is a complete lack of understanding of developmental genetics. What we typically find are changes in the pattern of expression of developmental genes, not wholesale losses. In the stickleback, Pitx1 is still there; what’s different is that the places in the embryo where it is turned on have changed, the map of the pattern of gene expression has shifted. You cannot describe that as simply a broken gene. Similarly, in the mouse, Hoekstra showed that the expression of genes that reduce pigmentation has expanded. We’ve seen the same thing in the blind cavefish; a creationist looks at it and says it’s just broken and has lost its eyes, but the scientists look closer and see that no, the fish have actually increased gene expression and expanded the domain of a midline gene.
Just wait for the detailed analysis of jaw morphology in cichlid fishes. These animals have radically different variants in feeding structures, which is thought to be the root of their adaptability and the radiation of different forms, and I guarantee you that the creationists will ignore the morphological novelties and focus on the fact that to achieve that, some genes will be downregulated (I also guarantee you that there will be such shifts in expression). It’s “all breaking things and losing things”, after all; just like baking a cake involves breaking eggs.
I don’t know how the creationists fit known variations in the coding sequences of genes (how do you translate a single-nucleotide polymorphism into their vision of all change being a matter of losses?) into their idea that all evolution is a matter of breaking DNA, or how they can claim all novelty requires a designer when people can track the progression of morphological shifts in the tetrapod transition, for instance, across tens of millions of years. It seems to be their desperate 21st century excuse in the face of the overwhelming progression of information from 21st century biological science.
Nelson ends his skewed summary of the meeting with the comment that “It’s a heck of a lot of fun to attend a conference like this, if you don’t mind being the butt of jokes.” I’m sure. I suppose Nelson could have even more fun if he put on a dunce cap and drooled a lot, because that’s basically his role at these meetings anyway — he’s the butt of jokes because he shows up and then happily demonstrates his ignorance about what’s going on. It’s not a role I’d enjoy, but the gang at the clown college called the Discovery Institute have a slightly different perspective, I suppose.
John Morales says
baju, you mean expelled? ;)