Coelacanth: Making the Most of an Unevolved Fish

Posted on April 18, 2013 in Darwin and Evolution, Dating Methods, Dumb Ideas, Fossils, Genetics, Marine Biology, Media

The coelacanth genome has been sequenced.  Does it show evidence for evolution?  Only to those with a good imagination.

The genome was published in Nature this week.  Science Now put the problem with coelacanth into perspective:

The coelacanth isn’t called a “living fossil” for nothing. The 2-meter-long, 90 kg fish was thought to have gone extinct 70 million years ago—until a fisherman caught one in 1938—and the animal looks a lot like its fossil ancestors dating back 300 million years. Now, the first analysis of the coelacanth’s genome reveals why the fish may have changed so little over the ages. It also may help explain how fish like it moved onto land long ago.

It may, but then again, it may not.  That’s the challenge facing evolutionists.  Why hasn’t this fish changed under the inexorable power of natural selection for 300 million years?  Why hasn’t it moved onto land?  Why does it still lurk in deep underwater caves, not using those lobed fins for walking?

So what’s the reason the coelacanth hasn’t evolved in 300 million years?  Answer: “The coelacanth genes changed at a ‘markedly’ slower rate than those from other animals,” Science Now said, without explaining why this fish escaped a natural law of evolution.  Must be some new kind of law:

The slow rate at which the fish’s genes change demonstrates that some animals evolve more gradually than others. The coelacanth looks primitive, but looks are difficult to quantify, whereas DNA sequences are not, Ahlberg says. “The fact that their proteins evolve slowly underscores that there is a real phenomenon going on here.

A real phenomenon, like creation?  Like stasis?  Like falsification of evolution?  Yes, there is a real phenomenon there.  As for how this genome might explain how fish moved onto land, the scientists brought in mighty mouse:

The authors located a fragment of DNA within the coelacanth’s genome that is also found in land vertebrates but not in fish without lobed fins, such as tuna, tilapia, and sharks. Because researchers cannot study live coelacanths in the laboratory, they inserted the fragment into a mouse embryo in order to learn what it does. The fragment activated a network of genes that forms bones in wrists, ankles, fingers and toes. Although it’s not yet clear what the DNA fragment’s function is within coelacanths, the authors suggest that it was key to forming the ends of limbs that helped a fishlike animal crawl out of the water.

But the genes are HOX genes, upstream switches that control downstream development.  They are not going to switch on a radius, ulna, wrist, or digits if the downstream genes aren’t there for them.  These same HOX genes didn’t help the coelacanth develop limbs or crawl out of the water for 300 million years.  So where is the purported “fishlike animal” where it did happen?  The researchers don’t know what these genes do in coelacanths.  If they did nothing, wouldn’t selection purge them instead of maintaining them for no good purpose?  It’s not clear how this experiment helps the evolutionary story.

Chris Woolston, writing for Nature about the genome, quoted one of the researchers (Chris Amemiya) saying, “The coelacanth is a cornerstone for our attempt to understand tetrapod evolution.”  Woolston concurred that coelacanth is a living fossil, but he didn’t add anything new to the evolutionary tale, except to debunk an old one:

Ending one long-standing argument, analysis of the coelacanth genome clearly shows that it is not the closest living fishy relative to tetrapods, Amemiya says: that honour belongs to the lungfish. However, he adds, the lungfish genome is unlikely to be sequenced any time soon because it is much larger and more complicated than that of the coelacanth.

How that helps the evolutionary story is also unclear: a more complicated, larger genome is ancestral to tetrapod genes?  Why would that be?  Woolston described how slow the genome evolution has been between two separated populations of the fish:

Scientists already had hints of the coelacanth’s sluggish evolution. In a 2012 study, researchers in Japan and Tanzania compared the DNA of the African and Indonesian coelacanths. Specifically, they looked at HOX genes, which help to guide embryonic development.… Even though the two species separated, by one estimate, perhaps 6 million years ago, their genes are remarkably similar. For these particular genes, the difference between the two species of coelacanth was about 11 times smaller than that between the HOX genes of humans and chimps, two species that parted ways perhaps 6 million to 8 million years ago.

The paper says they are 99.73% similar.  To explain this non-evolution, one of the researchers offered this idea: “It is impossible to say for sure, but the slow rate of coelacanth evolution could be due to a lack of natural-selection pressure,” Kerstin Lindblad-Toh said.  Natural selection is not really a pressure, though.  It’s only like a bumper in a pinball game, not one of the paddles operated by the mind of the player.  Woolston said that transposable elements, a form of non-coding DNA, have moved around, but Amemiya quickly added that their role in evolution is “speculative” and its significance is not clear.

So even though the genome paper said that coelacanth DNA is “a blueprint for understanding tetrapod evolution,” very little evidence supporting tetrapod evolution was offered.  “The slowly evolving coelacanth” was a major subsection of the paper.  Their last sentence provided only wishful thinking: “Further study of these changes between tetrapods and the coelacanth may provide important insights into how a complex organism like a vertebrate can markedly change its way of life.

That was the 7th use of “may” in the paper, along with 5 instances of “suggest.” Evidence for positive selection was also put off into the future: “A closer examination of gene families that show either unusually high or low levels of directional selection indicative of adaptation in the coelacanth may provide information on which selective pressures acted, and which pressures did not act, to shape this evolutionary relict.”  By “evolutionary relict,” they really mean something that didn’t evolve for 300 million years.

Nevertheless, the news media jumped onto the meme that the coelacanth genome “might” provide insight into evolution.  The BBC News said, “The work also shed light on how the fish was related to the first land-based animals” (but it wasn’t related, the researchers had admitted).  PhysOrg had a clever way to spin-doctor the anti-evolutionary evidence: it said the genome provided “Unexpected insights from a fish with a 300-million-year-old fossil record.”  National Geographic focused on the notion that this fish “evolved more slowly” than other animals.  Live Science used the power of suggestion in its headline, “Fish DNA Makes Limbs Sprout in Mice,” even though the HOX genes studied are far upstream of limb formation and have nothing to do with arm bones, wrists and fingers in a fish.

None of the media recognized that the evidence contradicts evolutionary theory, even though the coelacanth, with its lobed fins, had been promoted as Exhibit A for evolution by Darwinists before one was found swimming in the Atlantic in 1938.

If lies and misdirection were physical crimes, evolutionists would be convicted of terrorist bombings.

 

 

3 Comments

Plazatoro April 18, 2013

Amazing! The striking evidence against evolution is turned into “evidence” for evolution. Abracadbra

juanA April 18, 2013

The evolutionists, no doubt, have an experimented teacher that is know from old times like “the father of the lies”, among other titles. He is so smart that he is working nowdays with great freedom… when almost nobody believes in him.

Pikaia April 18, 2013

The Hox gene was probably used for some other purpose in the coelocanth, but the point is that it turns on arm and wrist formation in tetrapods and isn’t in any other fish except coelocanths and lungfish. Weird how similarities in bones and anatomy that seem to imply evolution are matched by DNA, too. The author asks where the fishlike animal is. Where did it happen? In Canada, for one. I believe that’s where Tiktaalik, a fishlike animal that could support itself on bendable, jointed fins was found. Panderichthys is another example of a fishlike animal. Acanthostega is an early tetrapod with eight fingers, Ichthyostega has seven. Later ones have five. So some parts of the spectrum from fish to amphibian and fin to limb have been found.

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