Scorpion tail and peacock tail are suddenly unlocked on one of my games, and that tribe has never even seen a nicheling with those genes before.
Also, the requirements for flying genes are odd. On that same game, where I've never done a flying action, the beak is already partially unlocked. And even though the wings get unlocked by obtaining the gene on a nicheling, two prerequisites for it were perform fly and swooping down on prey.