Creationists and Y Chromosomes

Posted 3 October 2010 by Skip

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. Additional notes: 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?

155 Comments

mrg · 3 October 2010

I’m starting to like Todd Wood, an actual honest creationist.

Ya gotta like the guy. I think partially it's just out of the sheer amazement of running into a creationist who isn't trying to run a scam. If he comes up with creationist arguments for his case, I'll actually read them. They might be wrong, but at least I won't assume they're wrong before I get past the title.

Rhacodactylus · 3 October 2010

Never let facts get in the way of a good story.

~Rhaco

Mike Hanson-Haubrich · 3 October 2010

Am I missing something? How long have primates been around? Are they correct in saying that "primate sex chromosomes are hundreds of millions of years old?"

Skip · 3 October 2010

I assume they mean the ancestral chromosome are hundreds of millions of years old?

Skip · 3 October 2010

Woops, meant to include the paper they reference. Haven't checked it myself, but might be enlightening on that points.

Lahn, B. T. & Page, D. C. Four evolutionary strata on the human X chromosome.
Science 286, 964–967 (1999).

Helena Constantine · 3 October 2010

Can't say I'm too impressed with wood. First of all he does allow comments on his blog. Then about a years ago I found an entry he made saying that the tower of babel story about the confusion of languages is literally true. Since I'm a philologist, I tracked down his e-mail address and sent him an e-mail asking how he handles a list of facts that can't possibly be explained by that story (like where did English, which is not much more than a thousand years old, come from, and if it developed from Germanic predecessors as Philologists think, why couldn't they have evolved from proto-Germanic, and that from Proto- Indo-Euroepan), but he never bothered to answer. This suggests to me that he is unable to argue on the subject, but is nevertheless willing to assert a definite opinion, which seems just like normal creationist operating procedure.

Glen Davidson · 4 October 2010

Oh yes, Luskin was telling essentially the same lies, it's just that he admitted that the y-chromosome diverged far more than most of the rest of the genome.

But see, we have these "assumptions," like that Yahweh isn't inordinately interested in our sex lives and changing sex chromosomes. Or something.

And rearranging chromosomes (the amount of which shows the same remarkable evolutionary changes), which doesn't look like any kind of design that we know, is just one of those playful things that middle eastern deities love to do. Or something.

Apparently evolution can't affect some parts of the chromosome more than others, thereby telling us something. Except that if everything did change at the same rate, well, wouldn't that be remarkable, almost miraculous?

So there you go. Everything in life shows design, and cannot fail to do so. Just like, ahem, it says in the holy writings. But don't you dare suppose that ID is religious in nature, only something that remarkably backs up religious (Xian, esp.) claims without bias being involved at all.

Glen Davidson

Glen Davidson · 4 October 2010

Oh, I guess I should link to the Luskin article. It doesn't really say much, just implying that evolution is put into dire straits because of the differential rate of change because, um, you know, everything we find just plain "explodes" evolution, don't you know. Or something.

Glen Davidson

hoary puccoon · 4 October 2010

Wouldn't it make sense that two very closely related species would have more differences in their sex chromosomes than in the average of their DNA? Aren't hybrids usually at a selective disadvantage? So, different mutations in their sex chromosomes would have a selective advantage; different mutations in their protein-generating genes would tend to have a selective disadvantage; and differences in pseudogenes would have little or no effect on survival.

Is that correct, or am I way off base?

DS · 4 October 2010

hoary puccoon said: Wouldn't it make sense that two very closely related species would have more differences in their sex chromosomes than in the average of their DNA? Aren't hybrids usually at a selective disadvantage? So, different mutations in their sex chromosomes would have a selective advantage; different mutations in their protein-generating genes would tend to have a selective disadvantage; and differences in pseudogenes would have little or no effect on survival. Is that correct, or am I way off base?

Sounds about right to me. For one thing, Y chromosomes have a lower effective population size, so drift would occur faster. For another thing, selection would be greater for Y linked genes, since mutations could not be masked in the heterozygous condition. So sure, on average, one might expect the divergence to be higher on average for Y chromosomes than other parts of the genome. Interestingly enough, when one reconstructs recent human evolutionary history using Y chromosome markers, the answer is exactly the same as that produced by nuclear or mitochondrial markers. Just one more thing that creationists cannot explain.

Skip · 4 October 2010

Helena wrote:

Can’t say I’m too impressed with wood.

Well, he IS a creationist after all, but he's far more often willing to concede the actual science than Ham, Hovind or the pathologically dishonest Casey Teddy Rupskin. (Ooh, nothing cute and cuddly about that. I just creeped myself out.)

mrg · 4 October 2010

Skip said: ist after all, but he's far more often willing to concede the actual science than Ham, Hovind or the pathologically dishonest Casey Teddy Rupskin.

Oh, you mean Denyse O'Luskin and Casey Leary? Wood cannot maintain his creationist beliefs without SOME selective reading of the evidence -- I mean, creationism can't EXIST without selective reading of the evidence, it's only the hot air that keeps the gasbag in the sky. However, the amount of evidence that he DOES concede is so staggering that it amazes me he clings to creationism at all and hasn't jumped the barrier to TE yet ... or possibly adopted Denis Lamoreaux's concept of "evolutionary creationism". Mind you, I don't endorse concepts like "evolutionary creationism", but I do find them amusing.

Aagcobb · 4 October 2010

mrg said: However, the amount of evidence that he DOES concede is so staggering that it amazes me he clings to creationism at all and hasn't jumped the barrier to TE yet ... or possibly adopted Denis Lamoreaux's concept of "evolutionary creationism".

Not that surprising if you assume that, like Kevin and Larry, his theology requires him to believe that his salvation depends on the Bible being literally true. The difference between him and them being that he has the education to know that standard creationist claims are a load of crap.

Rolf Aalberg · 4 October 2010

I can imagine how hard it must be to let go dreams of a heavenly afterlife, especially if you're in the company of people sharing the same dream.

Wheels · 4 October 2010

Aagcobb said:
mrg said: However, the amount of evidence that he DOES concede is so staggering that it amazes me he clings to creationism at all and hasn't jumped the barrier to TE yet ... or possibly adopted Denis Lamoreaux's concept of "evolutionary creationism".
Not that surprising if you assume that, like Kevin and Larry, his theology requires him to believe that his salvation depends on the Bible being literally true. The difference between him and them being that he has the education to know that standard creationist claims are a load of crap.

I don't have much in the way of an in-depth education, but even my technical college's Introduction to Logic class gave me enough to understand that standard Creationist claims are a load of crap. I have a hard time thinking that everyone from Dembski to Luskin are really that badly off in terms of the book learnin' they received. Rather I think it's just a choice to be less critical of their own knowledge (or their peers') than they should.

jaycubed · 4 October 2010

Our local Wed. night street markets are over until next summer, so I miss arguing with the creationist proselytizers (this year I have been focusing on how they all seem to use Bibles rewritten in the '70s [NIV, ESV, Living Bible] to eliminate the contradictions in Genesis, and how such Bibles are by their own standards blasphemous. It is fascinating how terrified they become of their Bibles when I whip out my copies of the Peshitta & Tanach (along with printouts from the KJV, Septuagint & Vulgate). They are typically either afraid to look at their Bible or hold it out as a shield).

One thing they always seem to say is, "Nobody understands evolution". When I respond, "That's silly. I understand evolution. What do you want to know?", the conversation ceases and they repeat like a mantra, "Nobody understands evolution".

Did you want to know about cosmic evolution?