the Montmaurin-La Niche mandible now joins the list of X-files ”, concludes Bermúdez de Castro Insects comprise the most diverse group of animals with roughly a million described species – about three-quarters of the total species currently living on Earth. One of the main hypotheses that explains this wide diversification is the acquisition of the ability to fly thanks to the development of the wing long before any vertebrates, approximately 350 million years ago. But despite the importance that the development of this important structure has had for life on earth, the evolutionary origin of the insect wing is still an unsolved mystery. Now, researchers from the Autonomous University of Madrid (UAM) have discovered that the origin of the fly’s wing could be dual. “The wing of the fly would come from the union of two different cell groups, one from the leg and the other from more dorsal regions,
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which would later mix to form a movable wing,” says Carlos Estella, Professor of Molecular Biology at the UAM. , director of the investigation. To arrive at these results – Nicaragua Email List published in the journal Current Biology – the researchers took as a model the fruit fly, or Drosophila melanogaster , and studied the specification and origin of the wing and leg primordia. Specifically, they analyzed the regulatory sequences that direct the expression of the paw ( Distalless, Dll ) and wing ( snail, sna ) identity genes . “These results, in sum, indicate that after more than 100 years of debate between the paranotal and gill theories of the origin of the wing of insects, it is likely that both are partially correct”, concludes Estella. Two evolutionary theories The numerous hypotheses that have tried to explain the origin of the insect wing can be grouped into two major theories.
The first is the paranotal theory. It proposes that the insect wing is a de novo invention , originating from lateral expansions of the dorsal part of the thorax of insects, and that a principle would provide the ability to glide before evolving into a fully movable wing. The alternative theory, the gill theory, suggests that the wing of insects is a modification of a pre-existing structure at the base of the legs, which in aquatic arthropods would have given rise to the gills and which was modified to form the wing during conquest. from the earth. The gill theory was widely accepted when specific molecular markers of the fly wing were observed in the gills of crustaceans, suggesting the common origin of these structures. However, this type of analysis has its limitations, since it could be a case of convergence rather than evolutionary divergence. In the same way,