User blog comment:Miskos3/Fairy Tail 520: Dragon or Demon, Review/@comment-4933386-20170205092919/@comment-1776824-20170206011834

It's more like the seed is planted when the dragons enchant you with their magic power. You can still have the magic without the seed. It's just that the seed will eventually turn you into a dragon. The dragon seed isn't linked to dragon slayer magic itself, just linked to slayers turning into dragons. The two seeds are similar, but fundamentally different in that regard.