Sonic the Hedgehog different media including animation, comic books, and a Hollywood film. The first "Sonic" game, "Sonic the Hedgehog", is a platform game released in 1991. Players control the anthropomorphic blue hedgehog Sonic, who can run and jump at high speeds using springs, ramps, and loops. Sonic must stop Dr. Robotnik from taking over the world using the Chaos Emeralds. "Sonic the Hedgehog 2" (1992) increased the overall size and speed of the series' gameplay and was the second best-selling Genesis game. It introduced Sonic's sidekick and best friend, Miles "Tails" Prower, who followed Sonic throughout the game, and allowed a second
Sonic hedgehog including the limb and midline structures in the brain, spinal cord, the thalamus by the "zona limitans intrathalamica" the lungs, and the teeth. Mutations in the human sonic hedgehog gene, "SHH", cause holoprosencephaly type 3 HPE3 as a result of the loss of the ventral midline. Sonic hedgehog is secreted at the zone of polarizing activity, which is located on the posterior side of a limb bud in an embryo. The sonic hedgehog transcription pathway has also been linked to the formation of specific kinds of cancerous tumors, including the embryonic cerebellar tumor, and medulloblastoma, as well as the progression