Microscopic hair-like cilia have great responsibility in many parts of our body. Yet they are simply conglomerations of tube-like proteins. Acting like road-sweepers on the cells lining our throat they expunge bacteria ridden mucous into the stomach in coordinated waves. They also play a role in our sense of sight. Each light-collecting cell in our eyes contains a cilium that directs photosensitive pigments to the surface where they detect light. Zebrafish eye development is similar to ours, so they are a useful research model. Normal cilia keep pigments in position (shown in green, left image). But in fish without a gene called IFT88, cilia fall apart and pigment accumulates (swathe of green in the right image). The result is a lethal concentration that destroys the cells. Healthy cilia are equally important in our ears and nose.
Written by Charles Harvey
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