Once More Unto the Breach (Or Close it with Butterflies)

This is what, three in a row? Brian Thomas again shows his ignorance of Natural Selection. Today, Butterflies Mimic Other Species with ‘Amazing Supergene’. At least there’s nothing wrong with the title

Examples of the genus Heliconius, famous for it's mimicry (modified)

The DpSU is reporting on the recent study in Nature, Chromosomal rearrangements maintain a polymorphic supergene controlling butterfly mimicry, and an associated news report, ‘Supergene’ is key to copycat butterflies. Mimicry, as B.T. also begins, is when one species of animal tries to look like another, preferably a poisonous one. This is so that predators are less likely to prey on it, having come to learn that the mimicked species is unpalatable, and avoid any thing looking similar to it like the plague. This is aided by the poor eyesight of many animals – not everything sees like you do (or even like me, and I have a score of -6 when it comes to glasses). Even with 20/20 human vision it isn’t easy to reliably tell apart the two pairs on the right.

Now, what are the genetic mechanisms behind this? Taking the broader route, we can see that it wouldn’t be hard to evolved mimicry – if predators have bad eyesight, in bad light one butterfly looks like another, and the more situations a butterfly can look like a more poisonous variety the better for it, so there’s no problem there. But until now it was unknown what underlaid all of this.

The Nature paper shows that the the mimicry is made by a ‘Supergene’. That is to say, a collection of genes that function as a single unit. You may be aware that this fits the definition of ‘Gene’ in Dawkin’s The Selfish Gene. Also interesting is the ‘polymorphic’ nature of the Supergene, which we shall call P as the Nature paper does. There are multiple forms of P that exist in the species studied, Heliconius numata, which cause different mimicry patterns despite being apparently only rearrangements of each other.

Enter Genetic recombination (stage right), the process by which large sections of a genome can be moved from place to place. Why doesn’t it break up P? Obviously it has in the past, to make the multiple forms. But it should break it up much more, including into many unworkable forms.

The study apparently found that recombination apparently had a role in the creation of P, but that it generally doesn’t break it up again. From the abstract alone I can’t tell if they know why – in any case you always need to keep a reason around to get more funding for the next round.

Enter now Mr Thomas, stage left. He, of course, plays up the quotes in the news report about how it is “amazing” and “the stuff of science fiction.” However, scientists are not infrequently astounded by nature. We know that evolution can and will produce crazy things – the Lenski experiment is and was arguably even more amazing, for example. His more specific problem is about how an arrangement could have evolved, as you would expect from him.

The reason this supergene appears so amazing to evolutionists is because it is too well-organized to be a product of blind, unthinking evolution. But it does make sense if a Mastermind designed this genetic switching system to enable butterflies to express near-perfect mimicking patterns—not after millions of years of evolutionary trial and error, but in a single generation!

It’s not ‘too well-organised’, and anyway, that’s not what was amazing. What was amazing was the ability of P to be in different forms to change the mimicked pattern. And even this is only amazing in the sense that the first planetary nebular discovered would have also been ‘amazing’ – mostly because it is new and unexpected, not because it is impossible.

He continues along the organisation line:

The study authors admitted, “The origin and maintenance of adaptive multi-locus polymorphism [shuffling sets of genes] in the face of recombination is a longstanding puzzle in evolutionary biology,” meaning that nobody knows how unguided nature could have built such elegant genetic operations, let alone maintained them for a “100 million years of evolution.”

Look, Fermat’s Last Theorem (which you might have recently seen on google) was a “longstanding puzzle” for three-hundred and fifty eight years and it was still solved. “Longstanding” in biology is not nearly such a long period. And once again I must link to the Adrian Thompson DpSU to point out that elegant and complex things can and will be produced by Selection alone.

The study authors questioned the origin of the supergene structure that they discovered. Did the genes evolve first separately and then become organized into the highly structured and effective supergenes that exist today, or did a cluster of genetic precursors organize into supergene structures and then evolve from there into their current forms? Either scenario requires useless genetic sequence hanging around for vast time spans—a faith-based idea with no scientific support.

Why would there need to be useless genes lying around? There are plenty of largely useless genes in the genome as it happens – recombination can also copy genes, leaving multiple instances which can be used or not used, and if they aren’t genetic drift can randomly change segments without fear of selection killing it off. And even then, there is no reason why the genes couldn’t work when they were separate, but now can’t now that they have adapted to being together. We don’t know now, but doesn’t mean that we never will. For example, we might find in other species mimicry that doesn’t involve supergenes. I would guess also that to a certain degree both processes would have had to occur. First, the genes would have evolved separately, then P would have formed and further evolution would have happened. The question is how much time was spent on each phase? Currently it seems that nobody knows…

The researchers suggested that the genes evolved first and later organized into the supergene system, but this is similar to looking at a computer keyboard and deducing that its keys started out in a jumbled pile and then self-assembled. Individual genes are already too complicated for any chance process to manufacture, let alone supergenes.

Look, natural selection is no more random than a pool of water flowing across a highly geologically active region – the landscape keeps changing, and the water just flows downwards, even if down is what up was only a moment before. Mr Thomas’ analogy is false.

The new study did help solve this “longstanding puzzle,” though not in the way the researchers indicated. Such effective all-or-nothing programming as that found in these mimicking butterflies could only have come about through the work of a master Programmer.

All-or-nothing programming is good programming? In the twenty first century, people expect their programs to continue working even if there is an error. Just thought that needed to be said…

By the way, this is a “Type AE” DpSU, seeing as I’m resurrecting the old taxonomy.

One thought on “Once More Unto the Breach (Or Close it with Butterflies)

  1. Pingback: Pseudohelpful Pseudogenes « Eye on the ICR


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