More specifically, the researchers demonstrated that bioluminescent organs originated repeatedly during squid evolution and then showed that the global gene expression profiles (transcriptomes) underlying those organs are strikingly — even predictably — similar. To confirm their hypothesis and findings, Oakley and Pankey enlisted the assistance of statisticians from the University of Washington and UCLA, who developed new statistical methods to test the idea of convergent (separately evolved) origins.
“I did find some individual genes that were counter to the main pattern, which means we can no longer study just one gene anymore in order to test these questions about the genetic basis of convergence,” said Pankey. “We’re at the point now where we need to — and can — study all of them.”
Some previous experiments have indicated that these squid use their bioluminescent capabilities for camouflage, as counterintuitive as that may seem. “If you imagine lying on your back in the deep ocean and looking up, almost all the light comes from straight above,” Oakley explained. “There’s no structure like walls or trees to reflect the light, so if there’s something above you, it’s going to cast a shadow. The squid can produce light that then matches the light from behind them so it blocks their shadow to a viewer below, which is a type of camouflage.”
The team’s results demonstrate that the evolution of overall gene expression underlying convergent complex traits may be predictable. This finding is unexpected and could indicate unusually strong constraints: The probability of complex organs evolving multiple times with similar trajectories should be vanishingly small, noted Oakley. Yet the team’s novel bioinformatic approaches indicate the evolution of convergent phenotypes is associated with the convergent expression of thousands of genes.
Laszlo Bencze notes what it sounds like:
This convergent evolution is so astonishingly unlikely that we would never expect it to occur via the evolutionary mechanism of random mutation and natural selection. But because we know that evolution by this process is a fact, we must now admit that statistically impossible things regularly occur in evolution because…well we don’t really know why but it’s clear that evolution has received a special dispensation from the laws of probability. Not once does it occur to him to doubt the evolutionary mechanism.
No, and it never will. Not until Darwinism is no longer an implicit requirement for tenure. (No that won’t make him doubt it, but others might.)
File under: Darwinism makes people stupid.
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