I am thinking of joining the study being conducted by the Sorenson 
Genealogy Foundation.  They are basically linking documented 
genealogies with yDNA and mtDNA markers so that people can use their 
database to get clues as to origins and to break throughbrick walls.

Has anyone looked into this or participated in this?  It is interesting 
to use their database.  I have been able to find matches for 18 of 19 
yDNA markers and the corresponding genealogies are mostly in Brazil!

http://www.smgf.com/about_smgf.html