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The tale of how the panda’s thumb evolved—twice


From Jane Qiu at Nature:

Giant pandas and the distantly related red pandas may have independently evolved an extra ‘digit’ — a false thumb — through changes to the same genes.

The two species share a common ancestor that lived more than 40 million years ago. Giant pandas (Ailuropoda melanoleuca) are distant relatives of other bears, whereas red pandas (Ailurus fulgens) are more closely related to ferrets. Both species subsist on a diet composed almost entirely of bamboo, with the help of a false digit.

In a new study, Wei Fuwen and Hu Yibo, conservation geneticists at the Chinese Academy of Sciences’ Institute of Zoology in Beijing, and their colleagues, produced the first genome sequence of the red panda and compared it with the giant panda genome. This comparison turned up a list of 70 genes that showed signs of evolutionary change in both species.

Has anyone run the odds on the likelihood of those seventy genes just happening to have changed in a way to enable this outcome on the basis of chance alone? Didn’t hear. Instead, we hear,

“Evolution, Stern says, ‘is actually much more predictable than anybody predicted.’More.

Well then, evolution is not what we have been told. But it is apparently difficult to have a discussion about that fact, even among top science boffins. Which is why the sea is currently boiling hot.

Note: Some Darwin fanboys actually named their blog Panda’s Thumb. Wonder if they would now…?

See also: Mechanism for photosynthesis found in primeval, non-photosynthetic microbe
So what kind of evolution should the rest of us call the pre-existence of needed traits? We’re not allowed to say “design,” right?


Evolution appears to converge on goals—but in Darwinian terms, is that possible?

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Um, I'm guessing that there aren't any, but doesn't the claim: "red pandas (Ailurus fulgens) are more closely related to ferrets" require SOME specific fossilized intermediates between the ancient sabre-toothed ferrets and modern red pandas? Or more simply, have the Darwinists identified ANY direct predecessor to red pandas? Or giant pandas? I get the idea that as far as anyone can prove, both modern animals appeared POOF! in their fully developed modern forms. Concluding that the DNA of the living modern animals is kinda sorta almost like the DNA of an ancient wombat isn't quite the same as showing a couple branches on The Tree of Life with points of diversion and actual descent with modification. Oh, wait. Is this another Just So story? Darwin gets a free pass if there's a Just So story. mahuna
Jon Garvey: I took a quick look--skimmed--your post. I believe your tongue was firmly planted in your cheek, no? The old-time regulars post so infrequently now, that's it's hard to remember who's who. PaV
Jon Garvey: The problem with Neutral Theory is that it can be used to explain anything; and, thus, explains nothing---or, should I say, very little. Neutral theory, used the way you are using it, is, I'm afraid, indistinguishable from 'magic.' There are 70 genes; each need, at an absolute minimum, one mutation. If all of these neutral mutations need to fall into place at once, the odds of that happening are 1 in 3^70, or roughly, 250^12, or 62,500^6, or (4 x 10^9)^3, or, roughly, 6.4 x 10^28: an exceedingly small probability. So, obviously, these neutral mutations need to be put into place little by little: meaning that they're just sort of in place when needed---magically, almost. The problem with this is that a "neutral" mutation obviously doesn't bring about much change---actually, almost "zero" change; otherwise, they wouldn't be "neutral." And 70 x zero=zero. Kimura didn't have such a benign understanding of neutral theory. The magic you invoke is you are effectively saying this: that which is 'unimportant' (i.e., neutral) becomes 'important.' But how exactly? There's a phrase that describes this process: "change, and hope." PaV
Lack of luck? |Yes, that would be it. Jon Garvey
Neutral theory explains it all quite neatly by luck.
Lack of luck? Mung
But, it’s simply tiring to point out obvious contradictions of neo-Darwinian theory when the response will be: “What’s the surprise? Given the right kinds of selection pressure, this is what we would expect.”
Ah PaV - that old-hat adaptationist line again. We're all Kimura fans now, so those 70 changes actually would have nearly all occurred via neutral evolution, with a bit of purifying selection to tidy things up in the phenotype. Population genetics proves it. We don't yet have a theory that explains homology in different lineages, but it's sure to turn up. There were after all a whole forty million years to diverge into bears and stoats and then converge into pandas :-). The adaptation question that need answering, since evolution is found by this researcher to be so predictably convergent, is why bamboo lemurs and bamboo rats, also obligate bamboo feeders and so under the same selection pressure, manage quite well without the extra pseudo-thumb. Neutral theory explains it all quite neatly by luck. Jon Garvey
I saw this article a week or so ago. Obviously, one wonders how, more or less, the same mutations in 70 portions two separate genomes came about in "random" fashion. But, it's simply tiring to point out obvious contradictions of neo-Darwinian theory when the response will be: "What's the surprise? Given the right kinds of selection pressure, this is what we would expect." The answer to this expected reply is: "Yes, you're right. In 5 trillion years, this is exactly what you would expect." It's very disheartening to see that this monumental dispositive evidence means nothing to "true believers" of Darwinism (or, neo-Darwinism, if that's more psychologically comfortable for you). Alas. PaV

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