a genealogist's sketchbook

In March, our patience in tracking down yet another distant Taylor cousin for DNA testing paid off. We now have a complete 67-marker Y–DNA profile for the earliest testable genetic ancestor of this family, Simon² Taylor of Old Rappahannock County, Virginia, who died in 1729. Five test subjects with known descent paths from Simon’s three sons known to have left male issue have been found.

What do these circled areas mean? By triangulating the genetic discrepancies uncovered, it has been possible not only to deduce Simon’s original STR values for 67 genetic markers on the Y chromosome, but also to deduce roughly where in the family tree each of these discrepancies must have occurred. In the above chart, the circled lines show individuals among whom a particular genetic mutation must have occurred. The most remarkable thing is that two mutations are pinpointed to a precise individual, Harrison⁴ Taylor (1735-1811), since descendants of two of his sons share the mutations, but a descendant of his brother Simon⁴ Taylor does not. The other mutations have only been pinpointed to particular lines of descent from intermediate individuals. Testing by other cousins with known ancestries would probably enable further precision on these mutations. The data table is given here:

All mutations are highlighted in blue. Providentially, the table shows that one of the five of us, kit no. 157892, preserves all 67 tested markers of his ancestor Simon² Taylor’s Y-DNA with no mutations; his values have been highlighted in orange.