I think this is a success story...

My putative oldest known male ancestor is Nicholas Knapp (1600-1670) who emigrated to America from England in 1630. Yesterday I got my 25-marker Y results from FTDNA which came out as R1b1c, which is consistent if somewhat generic. Searching for matches on ysearch, the closest one, lo and behold, is someone listing Nicholas Knapp at the head of the paternal line. Their sequence matched my results at 24 of 25 STR markers. The one difference was at 385a (11 vs. 10), so it's just a single one-step mutation off. Out of 25 markers, one mutation in 13 or so generations is about 50% probable by my calculation, using p=0.002.

Seems like correlating DNA results with known (or presumed) genealogical information has the most promise of bearing results & shoring up a genealogy. Hopefully more descendants of Nicholas will contribute test results and the statistics will get more solid as time goes by, the sequence of mutations worked out, etc.

Joe