The autosomal DNA tests offered by Ancestry and FTDNA (as Family Finder) only identify possible cousin relationships going back to common ancestors, generally no more than 300 years ago. The estimates these companies give showing the different proportions of ethnicity in a persons ancestry are very approximate and indicative only. Ancestry and FTDNA use different reference populations from each other - and so the results for the same person from the two different companies rarely are the same. Y-DNA testing gives a much more accurate picture, but only of the male/name bearing line.