Bonded

Draco Malfoy had always known that he was going to be an Alpha, like his father and his father's father.
What he didn't know was that the day Hermione was tortured under his eyes, something never seen before in the magical world happened: their magic created a bond.

Being an omega was a rare privilege among young purebloods girls. The gene was disappearing even in the oldest and purest families.
So how was it possible for that trait to show up in a muggleborn girl?