I’ve posted here before about Kevin and Larry, the creationist duo that treks every Saturday from the hinterlands of Wisconsin to downtown Madison and the farmers market around the square. They set up their Young Earth Creationism display and attempt to convert the heathens with claims of medieval knights defeating tyrannosaurus and Jesus riding into Jerusalem on a triceratops.
You can read my previous post on another server for details of my earlier encounters, but here I’ll just say that between the two of them they know and understand about as much actual science as you’d expect from two people who never read more than can be found on typical creationist web sites. I stop by their display on the weekends I make it down to the farmers market and often watch and participate in the exchanges they have with people from various backgrounds. I’ve never seen anyone give their material even the slightest serious consideration, have heard a lot of people offer blunt and unflattering appraisals of their display, and watched many a college student score big points against their creationist nonsense. But if they receive top marks for anything, it would be for persisting when there is absolutely no logical or practical reason to do so.
This past Saturday Larry asserted that an article in Nature proves human and chimp DNA is only 70% similar, new research that disproves earlier claims in the high nineties. Kevin began scrambling through their folder of creocrap and produced the relevant documentation. Was it the actual Nature paper? If you guessed yes, slap yourself across the face and go to bed without dessert.
Kevin handed me an article from the April 2010, Acts & Facts, published by the Institute for Creation Research titled “New Chromosome Research Undermines Human-Chimp Similarity Claims.” Without discussing it I told Larry I’d look up the actual paper and bring it to him next Saturday so we could compare the two. The weather was clear and cool, and I was already on the TZR so I was going to spend the rest of the morning carving up some back roads.
When I got home I read through the A&F piece and instantly realized something rather glaring. It doesn’t discuss any kind of comparison of human and chimp genome of any sizable portion, but rather as the title says the Y chromosomes of each. And further still, though ICR doesn’t say so, the Nature article makes it clear that the region of the chromosomes that were compared were only 25.8 megabases (Mb). In other words, the study dealt with less than 1% of the actual chimp genome.
So why did Larry claim that this paper shows that humans and chimps are only 70% similar? As I’ve found to be his modus operandi, Larry scans these little screeds for near-comprehensible tidbits and clings to them like Homer Simpson to the last pork chop. I found highlighted on the second page “[t]he researchers did postulate an overall 70 percent similarity…” and “only 70% of the chimp sequence could be aligned with the human sequence.” Remember, we’re talking about 25.8Mb on the Y chromosome.
So let’s look at the actual paper, which of course is only a Google away. “Chimpanzee and Human Y chromosomes are remarkably divergent in structure and gene content” appeared in the Letters section of Nature 463, 536-539 (28 January 2010). The meat of the research involved finishing “sequencing of the male-specific region of the Y chromosome (MSY) in our closest living relative, the chimpanzee, achieving levels of accuracy and completion previously reached for the human MSY.”
The researchers posit that since “primate sex chromosomes are hundreds of millions of years old, theories of decelerating decay would predict that the chimpanzee and human MSYs should have changed little since the separation of these two lineages just 6 million years ago.” And their research confirmed their hypothesis. “As expected, we found that the degree of similarity between orthologous chimpanzee and human MSY sequences (98.3% nucleotide identity) differs only modestly from that reported when comparing the rest of the chimpanzee and human genomes (98.8%).”
They also discovered something surprising: more than “30% of chimpanzee MSY sequence has no homologous, alignable counterpart in the human MSY, and vice versa.”
This is clearly big news and certainly worthy of investigation, but remember we’re talking about less than 1% of the total genome. It’s obviously incorrect to extrapolate this small sample across the entire genome of both species, and in fact the paper states that “[i]n this respect, the MSY differs radically from the remainder of the genome, where [less than] 2% of chimpanzee euchromatic sequence lacks a homologous, alignable counterpart in humans, and vice versa.”
But the ICR completely ignores this last statement that reiterates the prevailing view and instead uses the 30% difference in less than 1% of the genome to claim the new findings “contradict long-held claims of human-chimp DNA similarity.”
Distorting real scientific research to further their agenda is obviously nothing new for the ICR, and creationists in general, but participating in this exchange and experiencing firsthand how people like Larry and Kevin are manipulated by the professional anti-evolution organizations was enlightening.
I choose the word “manipulated” carefully, because I believe what is going on here is the ICR is exploiting the existential vulnerabilities in the theology of people like Kevin and Larry that the ICR actively shapes. And sells. Remember, the ICR makes their living, a very good one at that, convincing malleable fundamentalist Christians that their very soul, their place in either heaven or hell, depend on buying their books, toeing their party line, and coming to downtown Madison to regurgitate their nonsense.
It also makes me wonder why Larry adamantly refuses to look up primary references, and why he so forcefully argues these positions as if he really understands the science, and indeed almost physically dismisses those who disagree with him. I can only conclude that he’s become so convinced his actual Christian salvation is bound to believing this dreck he can’t bring himself to read the actual research.
That’s just sad.
I’m starting to like Todd Wood, an actual honest creationist. Here’s his take on the Y chromosome research.
In the case of the MSY, it’s important to keep in mind that the chimp MSY sequence reported by Hughes et al. is only 25.8 Mb. That’s slightly less than 1% of the entire genome. Given that fixed nucleotide differences between the human and chimp genomes are around 1%, having yet another 1% difference in the very different Y chromosomes doesn’t make the genomes that much more different than they already were.
For a bit of further reading on the topic, start with John Hawks from UW Madison. I can brag here and say, “Yeah, I know John.” He’s come to speak at our Science Pub events downtown Madison. Interestingly. I invited Larry to come to one of John’s talks to ask him in person about human evolution. Larry said he would on several occasions but was absent the day of the talk.
What’s that I hear? Is that the sound of a chicken squawking?