You can hold on to your butts thanks to #DNA that evolved in #fish
Making digits seems to involve #gene activity that was needed to make a #cloaca.
Fish that limbed #vertebrates evolved from don't have obvious digit equivalents, most common types of fish just have a large collection of rays supporting their fins.
It turns out hox gene activity in digits isn't the ancestral state; instead, it seems to have #evolved separately in the ray-finned fish and vertebrate lineages.
https://arstechnica.com/science/2025/09/distinct-digits-may-have-evolved-by-using-dna-that-makes-the-cloaca/