One-eyed creatures are not confined to the realm of Greek epic; such mutants can actually be found in nature. Defects in a gene called “sonic hedgehog” (which was, indeed, named after the videogame, by some no doubt particularly nerdy scientists) can, among other things, cause the two cerebral hemispheres of the brain to fuse, resulting in the development of a single, central eye.
This condition is occasionally seen in farm animals, for example when pregnant ewes consume the toxic plant Veratrum californicum, which disrupts the functioning of the sonic hedgehog gene. Cyclopia has even been seen in humans, with two known cases of children with Down syndrome having been born with one eye (or a single slit where the eye should be). Truth is not so much stranger than fiction, as it is the inspiration for it.
