Posts Tagged ‘junk DNA’
Osama bin Laden disproves Darwin!
Category: Creationism • Genetics
Posted on: May 4, 2011 7:32 AM, by PZ Myers
h, yeah…didn’t you know it was a crack team of Darwinist commandos who took out bin Laden, all to protect our secrets? David Klinghoffer doesn’t go quite that far, but he does demonstrate just how insane the gang at the Discovery Institute have gotten. After all, he does claim that Obama delayed the raid on Osama in order to promote creationism.
“President Obama is said to have known the whereabouts of Osama bin Laden since September but chose to wait until May to authorize action against him. Why the delay? Could it perhaps have been to provide a super-timely news hook for the rollout of Jonathan Wells’ new book, The Myth of Junk DNA? If so, an additional note of congratulation is owed to Mr. Obama.
How do you think OBL’s body was identified? By a comparison with his sister’s DNA, evidently those non-coding regions singled out by Darwin defenders, among the pantheon of other mythological evolutionary icons, as functionless “junk.” Indeed, the myth has featured in news coverage of Osama’s death. Reports the website of business magazine Fast Company:
Because your parents give you some of their DNA, they also give your siblings some of the same genetic code — which is why sibling DNA tests work. They sometimes concentrate on areas of the genome called “junk DNA” which serves no biological function but still gets passed along to offspring. By testing for repeat strands of DNA code in these areas, it’s possible to work out if two individuals are related as siblings.”
Uh, what? Wells is quite possibly the worst and most dishonest “scholars” employed by the Discovery Institute; I’ve been thinking of picking up a copy of his book simply because it will be hilariously bad. He won’t have shown the utility of junk DNA, but I’m pretty sure he will have do a silly dance while trying to justify his claims…rather like Klinghoffer here.
The reason junk DNA is useful for identification purposes is that it varies so much — it is subject to random change at a higher rate than coding DNA, because it is not subject to functional constraints. It’s been called a genetic fingerprint, and that’s a useful comparison. Think about your fingerprints: you can make a general argument that a pattern of ridges creates a texture useful for gripping, but it’s not important that there be a particular whorl or loop at a specific place. Junk DNA also lacks any specific function, but the analogy only breaks down because it also doesn’t seem to have much of a general function, given that some species like Fugu have lost significant quantities of it. The one purpose I find plausible is that, since cell growth is regulated by the ratio of cytoplasm to nuclear volume, adding junk can lead to an overall increase in cell size.
Somehow, the creationist incomprehension of the basic science is used to argue that evolution didn’t happen.
If Darwin is right, there ought to be huge swaths of ancestral garbage cluttering the genome, serving no purpose other than to identify otherwise unidentified forensic remains. So if those huge swaths turn out after all to be vitally important to the functioning organism, what does that say about Darwin’s theory? Ah, that’s exactly the question addressed in Jonathan Wells’ book.
Hang on. Darwin had no molecular biology and no genetics, knew nothing about DNA, and didn’t even know that chromosomes carried genetic information … he postulated the existence of migratory particles called gemmules that were the units of heredity (he was completely wrong, by the way). His claim to fame is discovering and documenting a mechanism that shapes adaptive heritability, and if anything, he thought selection ought to hone the heritable factors, whatever they were, to a high degree of optimality.
And now the creationists want to argue that junk DNA is a Darwinian prediction? They’ve totally lost the plot.
Explain this to me. Darwin, in their confused minds, claims that there ought to be lots of junk having no purpose other than to identify dead bodies. Junk DNA is used to identify a specific dead body, bin Laden’s. Therefore, Darwin is wrong. Even if I grant them their premise (which I won’t, because it is stupid), this doesn’t work.
Let’s see how many Darwin lobbyists have the guts and honesty to acknowledge that another icon has fallen. They have not, on the whole, left themselves a lot of room for deniability on this.
Gibbering lunatics like Klinghoffer and Wells are actually rather easy to deny.