Pedigree Question

So, I was reviewing this litter and noticed that Lean Mac is in both lines of the dam's pedigree. So, three generations ago, Lean Mac was the sire to both lines (father and mother) of the dam. Is that weird or is that common? Here is the dam's pedigree...

http://www.huntinglabpedigree.com/pedigree.asp?id=45333

Pretty common from what I have seen, line breeding on lean Mac is all

Yep.

THanks for the reply. I figured it must be somewhat common but didn't know if that was sort of incestual?

It's called line breeding if it works and inbreeding if it doesn't.

2x