The sponge genome reveals that, along the way toward the emergence of animals, genes for an entire network of specialized cells evolved. "This network laid the basis for the core gene logic of organisms that no longer functioned as single cells, but as a cooperative community of specialized cells all geared toward the survival of a complex multicellular creature," said Kosik.
Co-author Todd Oakley, professor in UCSB's Department of Ecology, Evolution & Marine Biology, explained that this work also helps scientists to understand cancer. "Once there is a transition from single cell to multicellular organisms, conflict is set up between the different cells of the multicellular organism," said Oakley. "It is in an individual cell's best interest to keep replicating, and this actually is what cancer is the uncontrolled replication of cells in the body."
Evolution had to solve the problem of how to police this uncontrolled replication, Oakley explained. Normally, body cells don't replicate out of control because there are policing mechanisms in place. When these policing mechanisms break down, cancer develops. "So in the history of animals, we can see this link with cancer, because the genes that are involved in the transition to multiple cells during evolution are also known to be linked to cancer," Oakley said.
As a neuroscientist, Kosik has great interest in synapses, which have a unique structure. The sponge has no neurons; however, it has the genes that encode for proteins which are used in other animals to build synapses. Synapses are a set of proteins that allow two neurons to talk to each other. They also allow a neuron to talk to a muscle and make it move. No other cells have synapses.
Kosik emphasized that scientists must go far
|Contact: Gail Gallessich|
University of California - Santa Barbara