Researchers at the Laboratory of Marine Biology (MBL) have solved the mystery of the origin of wings in insects, confirming the theory that they evolved from a growth, or “lobe”, at the level of the legs of an ancient crustacean.
A century-old mystery
As part of this work presented in the review Nature Ecology and Evolution, the team determined that after the ancient marine animal began to evolve on land, around 300 million years ago, a change occurred during its embryonic development, with the anchoring of one of the segments of its legs in its body wall. An adaptation that would have helped him to better support his weight in this new environment.
” In insects, the lobes of the legs have moved to the level of the back, and subsequently formed the wings “, Explain Heather bruce, co-author of the study. According to the researcher, one of the reasons it took a century to figure this out is that it wasn’t widely accepted until around 2010 that insects were very closely related to shellfish within the phylum of arthropods.
” Before that, the scientific community classified insects in the group of myriapods, including the centipede, because of their morphology. », Continues Bruce. ” Since myriapods were wingless, those of insects were considered to be entirely ‘new’ attributes, in the absence of corresponding structures in their supposed ancestors.. “
To solve the decades-old mystery of the appearance of wings in insects, the researchers drew on old scientific publications and performed advanced genomic analysis, involving the use of the gene editing tool. CRISPR-Cas9.
“Seeing my genomic and embryonic data confirming these old theories was astounding”
By comparing the genetic structure of the legs of a crustacean to that of various insects such as Drosophila, Bruce identified the genes corresponding to the six parts found in both crustaceans and insects. But the discovery of a seventh segment in the genus of crustaceans Parhyal intrigued the researcher.
” So I started going through the scientific publications and discovered that the idea that the proximal region [la plus proche du corps] legs had become anchored in the body wall in insects had been proposed in 1893 “, Explain Bruce. ” Then I came across this theory from the 1980s that the small lobes on this section of the leg then moved backwards to form the wings. Seeing my genomic and embryonic data confirming these old theories was astounding. “
According to the research team, it would have been impossible to unravel the mystery of wing evolution in insects without the powerful genomic tools available to scientists today.
” The idea that insect wings may have been an evolutionary innovation is fascinating », Declares Nipam Patel, director of MBL. ” But genomic comparisons show that nothing is entirely new and that it is possible to determine this origin. “