Logic and evolution:Darwin scientists find useless evolution (Introduction)

by David Turell , Monday, January 18, 2021, 01:25 (1404 days ago) @ David Turell

Unbelievable:

https://cosmosmagazine.com/nature/evolution/useless-evolution/?utm_source=Cosmos+-+Mast...

"Not all evolutionary shifts are, as we imagine, a driving force for improvement. On close examination, some represent meaningless change.

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“'How complexity evolves is one of the great questions of evolutionary biology,” says Joseph Thornton, of the University of Chicago, US. “The classic explanation is that elaborate structures must exist because they confer some functional benefit on the organism, so natural selection drives ever-increasing states of complexity.

“'But at the molecular level, we found that there are other simple mechanisms that drive the build-up of complexity.”

This is known as constructive neutral evolution (CNE). A molecular mechanism may evolve even though it provides no benefit just because it also provides no disadvantage – it simply happens because of biochemical quirk.

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"They used an elegant method called ancestral sequence reconstruction, in which they recreated the ancient ancestor of the steroid receptors before they’d evolved to work as dimers.

"It turned out that the ancient proteins functioned just as well as the modern, intricate dimers, despite the solo protein being significantly simpler; it wouldn’t matter if they’d never evolved at all. There was nothing beneficial about forming the molecular machine, but it became a fixed trait due to an evolutionary fluke.

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"The original formation of the dimer wasn’t harmful, and so wasn’t lost during selection. But once it happened, the proteins just couldn’t go back to the older, simpler method, and the machines hung around for hundreds of millions of years.

“'These proteins gradually became addicted to their interaction, even though there is nothing useful about it,” explains Georg Hochberg of the Max Planck Institute, Germany. “The parts of the protein that form the interface where the partners bind each other accumulated mutations that were tolerable after the dimer evolved, but would have been deleterious in the solo state. This made the protein totally dependent on the dimeric form, and it could no longer go back. Useless complexity became entrenched, essentially forever.”

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"Researchers resurrected the ancient proteins using synthetic DNA and introduced a very simple mutation to the gene. This triggered a chain of reactions that led to descendant proteins working exactly as they do today, suggesting how little is actually needed for neutral mutations to become established in the genome.

"At a small scale, there’s no “thought” of adaptation, there’s simply change based on chemistry and physics. At a higher, population scale, we can’t see these hidden complexities, so it all seems like adaptation. Quite simply, molecules are not intelligently evolved.

"Constructive neutral evolution is a beautiful theory that highlights exactly how complex evolution is, and that it goes well beyond “survival of the fittest”. Sometimes, things just uselessly evolve."

Comment: What happened to perfect natural selection which always makes the right choices? And note molecules are not intelligent, because they make these terrible mistakes!