I'm new to this research,very confused and you seem to know a great deal about this family. My GG-grandmother was Hettie Anna Alexander of Tennessee (James Franklin Alexander< Ebenezer Polk< Rankin Monroe< Ebenezer Crawford< Oliver).
The information on the DNA website, is it current and does the DNA support the claims that Oliver is the son of James (son of Jacob, son of Andrew)? Other people claim that Oliver was the son of John, and now I am thoroughly confused.
Are there any up to date references on the Alexanders that you would recommend? Also, an old post of yours states that this branch of Alexanders are not Scots-Irish, but English?