Scientists have long thought the humble sea sponge, an animal that feeds by filtering water through itself, forms the oldest group of animals on earth. But a new study claims that the comb jelly phylum is in fact older and carries genetic material from distant, non-animal ancestors.
Comb jellies, which look like miniature jellyfishes, use rows of cilia hairs to swim through the ocean and catch prey with tentacles that release a sticky, mucous-like substance. Like other animals, they meet the standard of having developed from a fertilized egg into a multicellular organism.
To determine whether comb jellies or sponges branched off the animal family tree first, researchers from the University of California-Berkeley and the University of Vienna tried genetic analysis, but their initial attempts led nowhere thanks to the extreme age of each group.
They next turned to chromosomes, specifically the arrangement of genes on each chromosome, hoping to ...
