Science is about inquiry, and sometimes what we think is true can be proven to be another thing. For years we’ve been providing materials and resources that position sponges as the first animal. Yet, scientists being the ‘ultimate questioners’, haven’t been completely willing to accept sponges’ position on the tree of animal life. There are two camps that are proponents for sponges or ctenophores (comb jellies). Now, through genetic research, there is strong evidence that comb jellies are the first animal.
Both of these animals are soft-bodied and don’t leave fossils. Researchers from, the Monterey Bay Aquarium Research Institute (MBARI), UC Berkeley and the University of Vienna mapped linkages between genes on specific chromosomes, which are deeply conserved throughout time. They analyzed the sets of genes that are always found together on a single chromosome, in organisms from humans and dogs to crabs and corals. The scientists provided “clear evidence that comb jellies were the first animals” followed by sponges. The comb jelly lineage is a unique one whose ancestors diverged before the common ancestor of all other animals.
“We developed a new way to take one of the deepest glimpses possible into the origins of animal life,” said Darrin Schultz, the lead author, a former researcher at MBARI who is now a postdoctoral researcher at the University of Vienna. “This finding will lay the foundation for the scientific community to begin to develop a better understanding of how animals have evolved.”
