A commercial ancestral Y-DNA test ONLY explores the paternal line, and it can therefore be used to pin one’s direct male ancestors to specific locations at specific time points in history.
(Updated December 2021) When commercial DNA testing began it focused completely on Y-DNA STR testing. While Y-DNA STR results can routinely be used to pinpoint a paternal origin
By examining the genetic distance between selected members of the R-M222 family and comparing it to the timetable developed by Scottish Origenes one can determine when the R-M222 Adam lived.