well, technically speaking, I think that eve if there is an animus' gene, it might need another to complete itself. so, for example, coral andd gill must have exactly half an animus' gene each to have animus' dragons. and every so often, the more non-animus dragons you marry, the lower your animus' percentage gets, so eventually, animus' powers can be bred out of DNA. meaning that arctic would've been a 'recharge' of the animus' gene, but he was taken away. but that's just my little pet theory.
