This site is like the IMDB for cannabis. Seriously, though very comprehensive database of genetics and strain profiles. If you haven't checked it out yet, you should. It's pretty cool.
This is a link to the family tree of "Blue Dream", for instance. I didn't know it was part Skunk #1. Very interesting stuff.
http://en.seedfinder.eu/strain-info/Blue_Dream/Clone_Only_Strains/family-tree/