Hey I just found the Black Family Tree and it is interesting how many of our familiar wizarding families were married into it!!
There are Flints (Markus Flint), Bulstrode (Milicent Bulstrode), Crouches, Longbottoms annd so many more!!
And did i mention that there is a Potter in there as well!! So that means that Sirius and Harry are distant blood relatives!!
I've worked it out!! Charlus Potter was married to Dorea Black who is Sirius's mother Walburga's Grandmothers Sister, so she is kind of Sirius's Great Aunt. So assuming that Charlus Potter is James father, then James is the cousin of Sirius's mother, and Harry, who is James son, is Sirius's cousin because it is the next generation down!! So Harry and Sirius may be cousins!!!!!!
And have u realised that is Harry dies that will be the end of the Potter family line!!!
So what do u think!!