Scientists make key discovery
Discovery is key to unlocking vertebrate evolution
University of Colorado Boulder-led research was distinguished in Nature, an international weekly journal of science, for a significant discovery in vertebrate evolution.
The findings reveal that the mysterious origins of vertebrates were likely made possible by an emergence of a new set of genes that made them distinct from invertebrates.
The research is special not only for its findings, but for the singularity of the lab that conducted the study. For a Nature paper, it is typical for the research to be an international effort from numerous, wealthy labs. The entirety of the work for this project was carried out by CU Boulder people at a CU Boulder lab.
“This paper was con
ceived, gestated, and born at CU,” said Daniel Medeiros, senior author of the paper and associate professor of ecology and evolutionary biology.
The scientists also managed to execute the final stages of the research amid pandemic lockdowns, when they did not have access to their lab.
“I’m proud of this group. It was just us nerds in our lab … coming to work and figuring stuff out,” Medeiros said.
The inspiration for the research derives from the long-standing questions surrounding the creation of vertebrates. Vertebrates, a group of animals that includes humans, appeared about 500 million years ago, he said.
They are different from their closest invertebrate relatives and have been fairly dominant predators ever since. However, it is unclear how this unprecedented evolutionary step occurred, he said.
A potential cause was discovered by comparing the sequencing of vertebrate and invertebrate genomes, the genetic material of an organism. They differ in the number and kind of genes giving cause to believe that this could be what prompted vertebrates to suddenly show up. Medeiros and his lab put this idea to the test.
The project can be described as “a window to the past,” said David Jandzik, the postdoctoral researcher for the project. “It allowed us to look back on our ancestors to see how maybe our ancestors looked 500 million years ago.”
Using CRISPR technology, a specially designed geneediting tool, scientists removed the differing parts of the genome, the part known as the endothelin signaling pathway, of the vertebrate genome from an ancient jawless vertebrate called the lamprey.
“We knocked out a gene family that’s unique to vertebrates and saw what happened,” Medeiros said. “If having these new genes is really important for making a vertebrate look unique, knocking it out should remove those unique features.”
After knocking out the gene family, the lamprey appeared to revert in steps to a more primitive, invertebrate-like animal. The results demonstrated that by removing some of the new parts, the animal de-evolved and lost traits that make vertebrates so special.
The finding is noteworthy because the two rounds of genome duplications are often “touted as a huge, monumental event” for vertebrates, said lead author Tyler Square, who recently completed his doctorate with the Medeiros lab. Despite its prominence in the discussion surrounding evolutionary genomic thought, there actually have been few examples found to support it.
“But this is a shining star example of exactly that,” Square said.