Natures wonders: diving kingfishers' special genes (Introduction)

by David Turell , Tuesday, October 24, 2023, 21:15 (394 days ago) @ David Turell

How do they protect their brains from impacts:

https://phys.org/news/2023-10-genes-kingfishers-brains.html

"If you've ever belly-flopped into a pool, then you know: water can be surprisingly hard if you hit it at the wrong angle. But many species of kingfishers dive headfirst into water to catch their fishy prey. In a new study in the journal Communications Biology, researchers compared the DNA of 30 different kingfisher species to zero in on the genes that might help explain the birds' diet and ability to dive without sustaining brain damage.

"The type of diving that kingfishers do—what researchers call "plunge-diving"—is an aeronautic feat. "It's a high-speed dive from air to water, and it's done by very few bird species," says Chad Eliason, a research scientist at the Field Museum in Chicago and the study's first author. But it's a behavior that's potentially risky.

"'For kingfishers to dive headfirst the way they do, they must have evolved other traits to keep them from hurting their brains," says Shannon Hackett, associate curator of birds at the Field Museum and the study's senior author.

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"Previously, co-authors Jenna McCollough and Michael Andersen, researchers from the University of New Mexico, led the team in using DNA to show that the groups of kingfishers that eat fish aren't each others' closest relatives within the kingfisher family tree. That means that kingfishers evolved their fishy diets—and the diving abilities to procure them—a number of separate times, rather than all evolving from one common fish-eating ancestor.

"'The fact that there are so many transitions to diving is what makes this group both fascinating and powerful, from a scientific research perspective," says Hackett. "If a trait evolves a multitude of different times independently, that means you have power to find an overarching explanation for why that is."

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"The scientists found that the fish-eating birds had several modified genes associated with diet and brain structure. For instance, they found mutations in the birds' AGT gene, which has been associated with dietary flexibility in other species, and the MAPT gene, which codes for tau proteins that relate to feeding behavior.

"Tau proteins help stabilize tiny structures inside the brain, but the accumulation of too many tau proteins can be a bad thing. In humans, traumatic brain injuries and Alzheimer's disease are associated with a buildup of tau."

Comment: this study shows convergent evolution, evidence for God Simon Conway-Morris uses. What the authors miss is the comparison with human high diving hands-first approach, breaking the surface of the water to protect the brain. The kingfisher's beak has the same effect.