Vertebrate Evolution Was Made Possible by Edn Signaling Pathway

A team at the University of Colorado in Boulder found that the endothelin signaling pathway gene family makes neural crest cell proliferation and specialization possible. The findings—published today in Nature—show that the gene family is crucial for the development of the head skeleton and other traits unique to vertebrates during embryonic development.

"Every animal essentially has the same basic core set of Lego pieces to make them. What this paper shows is that vertebrates have a few special pieces in addition to that, and we identify those special pieces," said Daniel Medeiros, senior author of the paper. 

In order to test whether or not the gene family could be responsible for the development of vertebrate species, the team studied the larvae of sea lamprey, identifying and removing the gene family. If their prediction was correct, the removal would revert a sea lamprey during its larval development into a more invertebrate-like worm, a close evolutionary ancestor. "We found that by knocking out this new gene family, you can almost erase most of the key vertebrate traits that make vertebrates special," said Medeiros.

While gene duplication is still an important part of the evolutionary process, they found that duplication was not as critical in giving rise to the special neural crest cell types that vertebrates evolved as was the emergence of this new gene family. “This finding is significant due to how rare it is to find clear roles for genes that are unique to vertebrates,” said lead author Tyler Square.  "We thought that gene duplication was the most important thing. But here, we found both of those things [new genes and duplications] happening at once," he concludes.