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 B. Lewis, identified genes that control the segmentation pattern of the "Drosophila" embryos. The "hh" loss of function mutant phenotype causes the embryos to be covered with denticles, small pointy projections resembling the spines of a hedgehog. Investigations aimed at finding a "hedgehog" equivalent in vertebrates by Philip Ingham, Andrew P. McMahon, and Clifford Tabin, revealed three homologous genes. Two of these, "desert hedgehog" and "Indian hedgehog", were named for species of hedgehogs, while "sonic hedgehog" was named after Sonic the Hedgehog, the protagonist of the eponymous video game franchise. The name was devised by Robert Riddle, who was a