The primary goal of the project has to be identifying the origins of James DAVIS and Thomas THOMPSON, if not through Y-DNA testing, then through FamilyFinder testing — or both.  Likewise, the origin of Sarah "Sally" (JONES) CLARK, mother-in-law to Isaac DAVIS, son of James.  Other issues in the recent generations of the family can be resolved with this testing — for example, we've already proven an adopted son is truly a THOMPSON — but breaking down these three "brick walls" is paramount.  Family genealogists have been researching these questions for at least the last century, when my great-grandmother, Maude Irene (THOMPSON) ROSE, and my aunt, Betty Ann (MATTHIESEN) COGLIATI, and others of their generations began the quest well before I was born.  Will our efforts bring us success, at last?  The more who participate in the testing, the more likely success becomes.

Update:  Y-DNA testing has confirmed that Isaac DAVIS is a son of James DAVIS (1744-1822) as long alleged.