Sponge Genes Hint at the Origins of Neurons and Other Cells

When the first sponge genomes were sequenced in the early 2000s, researchers were surprised to find that sponges not only have roughly as many genes as humans and other complex creatures but also have many of the same genes. Sponges are among the earliest branching lineages on the evolutionary tree of animal life; their simple bodies don’t even have a pattern of symmetry or a set number of parts.

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