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Using genomic and embryonic data, Bruce and her colleagues found evidence that this is the case. First, the proximal leg lobes become integrated into the body wall. Then, once there, the proximal segment migrates up and back, to later form the insect wing.
“The complementary view of leg genes and wing genes led these groups to agree on answers to some key questions about winged crustacean metamorphosis“two independent experts wrote in a review of the two studies in Nature Ecology and Evolution.
However, studies don’t agree on everything. The first study to support the hypothesis “dual origin”suppose, I think The proximal leg segments and the body wall both contribute to wing development.
The second paper proposes a more gradual and complex transformation, involving mainly the leg segments. The scientists found that the two most proximal leg segments first fuse into the insect’s body wall, and then only the most proximal leg segment squeezes backward to form the wing.
The differences are subtle, and more research is needed to work out which – if either – is more correct. But the similarities between the studies provide a compelling solution to the question of which previous theory about the evolution of insect wings is correct.
Researcher Bruce has argued for years that ancestral crustaceans once had eight leg segments. One of these, she argues, was incorporated into the body wall, whereas in fruit flies, one of these was incorporated into the body wall and the other into its wings later.
This makes the insect wing appear to have a dual origin, where the body wall and legs fuse to form the wings. When in fact, the authors say, the insect body wall itself originates from the proximal leg segments.
“While wings are a major development over the present-day insect body wall, they are derived from the leg segments of ancestral arthropods,” the researchers concluded.
It’s a neat idea that gives rise to a number of competing hypotheses, but it’s unlikely to end the mystery. In just the past 10 years, we’ve learned a lot more about insect evolution.
Before studying the genome, researchers didn’t even realize that crustaceans and insects were closely related in the arthropod family. That’s why many people thought insect wings had sprung up out of…nowhere.
Gills, segmented legs, and crustacean bodies now provide us with direct targets for study.
“People are very excited about the idea that something like an insect wing could be a new evolutionary innovation. But one of the stories that emerges from comparing genomes is that nothing is new. Everything comes from somewhere. And in fact, you can figure out where.”the researchers added.
Nature magazine concluded: “While the origin of insect wings remains a mystery, the work of both groups suggests exciting avenues for solving this mystery.”
According to Dan Tri