Natures wonders: echolocation in diverse species (Introduction)

by David Turell , Saturday, October 05, 2019, 23:57 (1874 days ago) @ dhw

A major study shows echolocation developed in many different sorts of organisms mutating similar genes in all of them, a form of convergence in evolution:

https://www.sciencedaily.com/releases/2019/10/191004105643.htm

"Insect-eating bats navigate effortlessly in the dark and dolphins and killer whales gobble up prey in murky waters thanks in part to specific changes in a set of 18 genes involved in the development of the cochlear ganglion -- a group of nerves that transmit sound from the ear to the brain, according to a new study.

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"The discovery solves a long-standing biological debate as to whether echolocating bats and whales have independently undergone many similar genomic changes "under the hood" to accomplish the same goal.

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"'Developmental biologists have long wondered whether, at the most basic level, something that's the same on the outside -- like species that use echolocation -- are the same on the inside. That is, do they acquire these traits through similar molecular changes? Now we know that not only is this true as least some of the times, but also that many of these changes occur in the coding region of the genome. It's fascinating."

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"'For a long time, biologists have wondered whether important evolutionary changes could occur through changes in the sequences of genes that are very similar across related species," Bejerano said. "These genes often control multiple functions in different tissues throughout the body, so it seems it would be very difficult to introduce even minor changes. But here we've found that not only do these very different species share specific genetic changes, but also that these changes occur in coding genes."

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"Remarkably, the researchers found that their unbiased analysis homed in on the cochlear ganglion as the single most affected tissue among echolocating mammals. In particular, 25 "convergent" amino acid changes occurred in 18 genes known to be involved in the development of the cochlear ganglion. Only two of the 25 changes had been previously identified in past echolocation studies." (my bold)

Comment: Chance evolution with chance mutations could not have achieved this result where diverse species all develop the same changes in the same genes; this is what Simon Conway -Morris calls convergence as a proof of God's control.