Evolution: a different view with loss of traits; not Behe (Introduction)

by David Turell , Wednesday, January 05, 2022, 21:06 (1052 days ago) @ David Turell

Flying fish research supports Behe, showing loss of function DNA change:

https://www.quantamagazine.org/flying-fish-and-aquarium-pets-yield-secrets-of-evolution...

"To escape predators beneath the waves, a flying fish can shoot out of the water and glide long distances because its paired pectoral and pelvic fins, longer and more rigid than those of other fish, act as airfoils. In a quirky triumph of evolution, creatures that were once strictly aquatic transformed into temporarily airborne ones through a few modifications in body shape.

"Recently, a group of researchers led by Matthew Harris of Harvard Medical School and Boston Children’s Hospital reported the genetic basis for the evolution of those unusual fins: Through an innovative combination of techniques, they discovered that changes in just two genes were sufficient to create the distinctive body shape of flying fishes. When those mutations occurred in a species of common aquarium fish, its proportions began to shift in similar ways.

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"To search for the genetic basis of the flying fish’s body shape, researchers in the Harris lab began by sequencing and comparing the genomes of 35 species of flying fish and their close relatives. By looking for regions of DNA that had changed unusually quickly between species, they identified genes that seemed to have evolved under selection pressure.

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"The researchers showed that in zebra fish, loss-of-function mutations in the leucine transporter cause all fins to be short, while the overexpression mutation of the potassium channels causes all fins to be long. Either of those mutations by itself produces a clumsy fish. But when the two mutations are combined, the resulting zebra fish has long paired pectoral fins and shorter median fins, exactly the form of the flying fish. (my bold)

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"The flying fish body plan evolved independently several times in various lineages, and it always relied on the same types of mutations in the leucine transporter and the potassium channel. The leucine transporter mutations in the different lineages are not identical, but they cause the same amino acid change — a clue that the lineages independently hit on the same genetic trick to evolve this shape. “Nature has targeted the same specific gene in a couple of different contexts,” said Sarah McMenamin, a fish evolutionary developmental biologist at Boston College."

Comment: more strong support for Behe's approach that evolution devolves to advance