Sonic hedgehog

Sonic hedgehog is a protein that in humans is encoded by the SHH ("sonic hedgehog") gene. Both the gene and the protein may also be found notated alternatively as "Shh".

Sonic hedgehog is one of three proteins in the mammalian signaling pathway family called hedgehog, the others being desert hedgehog (DHH) and Indian hedgehog (IHH). SHH is the best studied ligand of the hedgehog signaling pathway. It plays a key role in regulating vertebrate organogenesis, such as in the growth of digits on limbs and organization of the brain. Sonic hedgehog is the best established example of a morphogen as defined by Lewis Wolpert's French flag model—a molecule that diffuses to form a concentration gradient and has different effects on the cells of the developing embryo depending on its concentration. SHH remains important in the adult. It controls cell division of adult stem cells and has been implicated in the development of some cancers.

Discovery

The hedgehog gene (hh) was first identified in the fruit-fly Drosophila melanogaster in the classic Heidelberg screens of Christiane Nüsslein-Volhard and Eric Wieschaus, as published in 1980. These screens, which led to them winning the Nobel Prize in 1995 along with developmental geneticist Edward 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 a hedgehog.

Sonic the Hedgehog (character)

Sonic the Hedgehog (Japanese: ソニック・ザ・ヘッジホッグ, Hepburn: Sonikku za Hejjihoggu), trademarked Sonic The Hedgehog, is the title character and protagonist of the Sonic the Hedgehog series released by Sega, as well as numerous spin-off comics, five animated shows, and an animated OVA.

Sonic is a blue anthropomorphic hedgehog who has the ability to run at supersonic speeds and the ability to curl into a ball, primarily to attack enemies. Throughout the course of the video games, Sonic most commonly has to race through levels, collect power up rings and survive against a host of natural obstacles and minions to achieve his goal. While many individuals at Sega had a hand in Sonic's creation, programmer Yuji Naka and artist Naoto Ohshima are generally credited with the creation of the character.

The first game was released on June 23, 1991, to provide Sega with a mascot to rival Nintendo's flagship character Mario (see 1991 in video gaming). Since then, Sonic has become one of the world's best-known video game characters, with his series selling more than 80 million copies. In 2005, Sonic was one of the first game character inductees into the Walk of Game, alongside Mario and Link.