2. The gene that gives Hemingway's cats extra toes is named after a video game character.

2. The gene that gives Hemingway's cats extra toes is named after a video game character.

The reason the cats have extra toes, according to Kat Arney in the book Herding Hemingway’s Cats, is “a mistake in the control switch for a gene called Sonic Hedgehog. And yes, it was named after the video-game character.”
Arney writes that two German scientists coined the name after noticing fruit fly maggots with a gene expression were “unusually stumpy and covered in bristles,” so they “picked a name for the gene to reflect what these unfortunate creatures looked like: hedgehogs.” In the ‘90s, three types of the hedgehog gene were found in mammals; the third was named by Bob Riddle, who dubbed it Sonic after the hedgehog in his daughter’s comic book.