The lilies, it turned out, contained a poison, later dubbed cyclopamine, that stunted developing lamb embryos.

FORBES: Magazine Article

They published their discovery in 1998, and Beachy and others began exposing animals to cyclopamine to study its role.

FORBES: Magazine Article

Cyclopamine, it turns out, blocks the function of a gene called Sonic hedgehog that is essential for embryonic development but also plays a lead role in causing deadly cancers of the pancreas, skin, prostate and esophagus.

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All these mutations were done by physically changing the animals' DNA. It wasn't until Johns Hopkins' Beachy and his colleagues remembered reading about the Idaho lambs that they realized cyclopamine could be used as an easier on-off switch for the hedgehog pathway.

FORBES: Magazine Article