"Two of these genes, desert hedgehog and Indian hedgehog, were named for species of hedgehogs, while sonic hedgehog was named after the video game character Sonic the Hedgehog.[15][16] The gene was named by Robert Riddle, a postdoctoral fellow at the Tabin Lab, after his wife Betsy Wilder came home with a magazine containing an advert for the game Sonic the Hedgehog.[17][18][19] In the zebrafish, two of the three vertebrate hh genes are duplicated: SHH a[20] and SHH b[21] (formerly described as tiggywinkle hedgehog, named for Mrs. Tiggy-Winkle, a character from Beatrix Potter's books for children) and ihha and ihhb[22] (formerly described as echidna hedgehog, named for the spiny anteater and not for the character Knuckles the Echidna in the Sonic franchise)."