I'm Really Confused About Pedigree

[RollerDoc]

I know I will probably get hazed for this, but while doing some research on pedigrees, I noticed something that prompts me asking anyway.

In the example of Big Brown (surprise surprise).

His father was Boundary, whose father was Danzig, whose father was Northern Dancer.

His mother was Mien, whose father was Nureyev, whose father was Northern Dancer.


So my question is, how can Northern Dancer be Big Brown's great grandfather on both his father and mother's side? Unless he was adopted

Isn't that inbreeding?