One of the benefits of this, especially when the resulting files are added to yFull.com, is that timescale estimates are added to the branches being created on the yDNA tree of mankind.
A snapshot of the resulting tree as at Nov 2018 is on the Guild of One Name Study Histories pages
copied here:
Our Fairbairn (& matching Elliott) sub branch of I-Y7277 is
I-Y32666/ which as of Nov 2018 yFull estimated was formed 3800-2300 years before present, average 3000 (where "present" is 1950). The Most Recent Common Ancestor (MRCA) is estimated as 600 ybp (average of 900-325 ybp).
Underneath that branch we now have one branch without close matches on the known sub branches.
Then come two main sub branches:
- one estimated to have formed 600 ybp (average of 900-325 ybp), with a MRCA of 225 ybp
- one estimated to have formed 550 ybp (average of 900-225 ybp), also with a MRCA of 225 ybp
The latter has two separate branches of our Fairbairns, namely the Cockburnspath, Berwickshire branch and that of John Fairbairn/Bessie Flint who married abt 1725 in Melrose, Roxburghshire
So, with the earlier generic branch being a Fairbairn, it does look like these Elliotts sprang from a Fairbairn around 1400, or 1725, depending on whether you use the branch formation or the MRCA date.
It's sale time again at FamilyTreeDNA until the end of December, so an excellent time to get more branches represented by BigY testing (hint hint)
Some background reading from Roberta Estes DNA-explained blog as to Why the Big Y