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What links cyclops lambs, poisonous flowers, and six-toed cats? They're all involved in the story of a gene called Sonic Hedgehog - yes, that is its real name – which has its genetic fingers in all kinds of developmental processes. Sonic Hedgehog helps to decide how many bits you have, where they go, and whether you’re symmetrical, so it’s not surprising that when Sonic makes mistakes there can be serious consequences. We take a look at the mind-bogglingly intricate process of creating a body, and the key role our favourite blue hero plays in making sure everything goes to plan.

Dr Kat Arney is joined by hedgehog experts Dr Bob Riddle of the US National Institute of Neurological Disorders and Stroke, Professor Robert Hill of Edinburgh University, and Dr Natalia Riobo-Del Galdo of Leeds University.

Presenter: Kat Arney
Producer: Beth Sagar-Fenton