Progressive Loss of Function in a Limb Enhancer During Snake Evolution (2016)
cell.com
cell.com
It's about how limbless creatures emerge under genetic pressure from evolution, from the common fetal form which includes information to develop limbs.
How in the name of sweet balrog did a genetic process get called sonic hedgehog?
Researchers that discover things can name it wherever they want. This family of genes are all named after hedgehogs because it makes fruit fly embryos spiky if you knock the gene out.
> A picture can tell 1000 words - a look at drosophila hedgehog mutant