Sonic Hedgehog homolog (SHH) was a term used in one of the three proteins of a hedgehog. It can be found in other types of hedgehogs including thee mammalian hedgehog family and that of the desert and Indian hedgehog. Sonic Hedgehog is a secreted protein that causes the formation of cell proliferation, differentiation and migration. It acts by binding to other transmembrane.

It was first identified in 1978 on a book by Eric Wieshaus and Christiane Nusslein-Vollhard. The hedgehog genes were identified in the classic Heidelberg screens. Together with scientist Edward B. Lewis, identified the genes and let to the conclusion that these genes where used in the control and segmentation of the fruit fly embryos. During this stage that they found out that the hedgehog loss functions of the mutant phenotype which causes the embryos to be covered small pointy spikes all over its body.

The hedgehog homologues have been found out to have critical roles in development. Hedgehog homologues act as a morphogen involved in patterning body parts in the human body. It could either be a limb, spinal cord, or some parts of the brain. Sonic Hedgehog gene often mutated and cause holoprosencephaly type 3, which severely damages the ventral midline.

Recently it has been found out to link to the formation of certain types of cancers. It has been demonstrated numerous times that it attracts commissural axons at the ventral midline near the spinal cords. One of the most common thing that SHH attract is retinal ganglion cell (RCG) axons at low concentration and could either repel them at a much more concentration.

Before SHH is secreted in the cells it has been found out that it undergoes a series of steps. Freshly synthesized cells are commonly called as preproprotein. They weigh about 45 kDa a minute size for a cell. When it is secreted it contains short signal sequence that is recognized by the signal recognition during the translocation. Once translocation is finished, the sequence is signal is removed by signal peptidase in the ER. SHH undergoes another processing for it to generate a 20 kDa and 25 kDa, both have unknown signaling domain.

Sega might have been doing some extensive research in finding hidden names in real genes. Both Sonics name and Knuckles are both found in the gene itself. Finding names for video game characters is a daunting task. Extensive research has to take place in order to find that well suited name. Naming video game characters are one of the hardest thing to make. A game character could make or break the game itself. Thinking of a name that is both appealing and easily remembered by the people can prove to be a challenge for game developers.