What sponges lack, however, are a gut, muscles and neurons.
"This incredibly old ancestor possessed the same core building blocks for multicellular form and function that still sits at the heart of all living animals, including humans," said coauthor Bernie Degnan, a professor of biology at the University of Queensland, Australia, who collected the sponge whose genome was sequenced from the Great Barrier Reef. "It now appears that the evolution of these genes not only allowed the first animals to colonize the ancient oceans, but underpinned the evolution of the full biodiversity of animals we see today."
According to Degnan, essentially all the genomic innovations that we deem necessary for intricate modern animal life have their origins much further back in time that anyone anticipated, predating the Cambrian explosion by tens if not hundreds of millions of years.
"What marked the evolutionary origin of animals was the ability of individual cells to assume specialized properties and work together for the greater good of the entire organism. The sponge represents a window on this ancient and momentous event," said coauthor Dr. Kenneth S. Kosik, the Harriman Professor of Neuroscience at UC Santa Barbara and co-director of the Neuroscience Research Institute.
"Remarkably, the sponge genome now reveals that, along the way toward the emergence of animals, genes for an entire network of many specialized cells evolved and laid the basis for the core gene logic of organisms that no longer functioned as single cells," he said, "but as a cooperative community of specialized cells all geared toward the survival of a complex multi-cellular creature."
"The beauty of having this genome is that now we can ask about all known biological processes, and go through hundreds of genes to tell definitively whether or not o
|Contact: Robert Sanders|
University of California - Berkeley