Sponge cells hint at origins of nervous system

Sponges are expert filter feeders, straining tens of thousands of litres of water through their bodies every day to collect their food. And they do this without a brain, or a single neuron, to their name. Now, researchers have sequenced the RNA in various individual cells from a freshwater sponge (Spongilla lacustris) and found that sponges use an intricate cell communication system to regulate their feeding and to potentially weed out invading bacteria. The findings could help to understand how animals’ nervous systems evolved.