The Bio//Medical Enthusiast

How do our bodies know to grow our arms, legs, fingers and toes in the right places?

During pregnancy, the growing embryo has to express many genes to make sure the limbs grow properly. One of those genes is known as Sonic hedgehog (Shh). The purposes of Sonic hedgehog in the embryo are to control¹:

• The shape and size of the limbs.
• Where, how and which digits grow at the end of each limb.

But why is a gene named after a beloved video game character? You can thank researcher Robert Riddle for that.

During the 1990s, Riddle was studying the gene at the Harvard Medical School within Clifford Tabin’s research group; he was also the first person to clone it^2,3. Riddle was inspired to name the gene after Sonic because³:

1. He learned about the character through a comic book that his daughter owned at the time.
2. He felt that the name fit the “loud and boisterous” energy of the research group.

In any case, Sonic hedgehog is certainly more memorable than the gene’s original name: Common European Hedgehog³.

Further reading:

1. Tickle C, Towers M. Sonic Hedgehog Signaling in Limb Development. Front Cell Dev Biol 2017;Volume 5-2017; doi: 10.3389/fcell.2017.00014.
2. 2.         Riddle RD, Johnson RL, Laufer E, et al. Sonic hedgehog mediates the polarizing activity of the ZPA. Cell 1993;75(7):1401–1416; doi: 10.1016/0092-8674(93)90626-2.
3. 3.         Keen A, Tabin C. Cliff Tabin: Super Sonic – An Interview. 2004. Available from: web.archive.org/web/20051110080615/http://web.med.harvard.edu/sites/murmur/html/articles/041204/041204_akeen.asp [Last accessed: 4/2/2026].