M. Srivastava et al., "The Amphimedon queenslandica genome and the evolution of animal complexity," Nature, 466:720-26, 2010. Free F1000 Evaluation
The marine sponge Amphimedon queenslandica evolved from single-celled ancestors before the Cambrian explosion, making it one of the earliest multicellular organisms. However, when Bernard Degnan of The University of Queensland and colleagues analyzed the sponge’s genome, they saw that it shared genes that are characteristic of more complex animal traits, suggesting that these genes evolved before multicellularity itself.
The sponge carries genes that, in more complex animals, code for transcription factors involved in differentiation of muscles and nerves—despite not having a neuromuscular system itself. One theory proposes that Amphimedon is a “throwback,” having evolved to a simpler organism from a more complex ancestor, but according to Faculty Member Doug Erwin the new data do not support that point of view....
The presence of neural genes, which were likely to have served other functions in simple animals or protozoa, raises the question: "How did they get co-opted for nervous system development in later animals?” says Erwin. The next step, he says, is to determine the function of these genes in even more primitive organisms.
The finding was a surprise for Degnan, whose lab primarily works on mining the sponge’s biology for industrial applications. Amphimedon’s glass spikes, for example, have properties similar to fiber optic wires and have commercial relevance in nanotechnology and communication. Degnan plans to use what he learned from the sponge genome to modify the formation of the glass fibers.