Last updated September 10, 2023.
Ferguson surname within R1b-BY729 paternal line is clearly secondary, i.e. introduced by a non-paternal event (NPE). We are able to localize this event in time and space. There is yDNA tested Ferguson male with Hg CTS4089 whose paper trail goes to Richard Ferguson born 1765 in Virginia, died 1854 in Ferguson, Wilkes Co, North Carolina. His father is assumed to had been Thomas Ferguson, b. in Virginia ca 1740. Richard married Verlinda Triplett, a lady of a rather rare surname which is key to our conclusions. In 1754 in Prince William Co, Virginia, certain Elizabeth Ann Triplett (b. 1738) became the wife of John Brawner. This John, born in Charles Co, Maryland, in 1734, is also known to had carried CTS4089 since there is at least one yDNA tested Brawner male directly descended from him. This is hardly a coincidence.
Although available information is not enough to tell what the exact relations among Fergusons, Brawners and Tripletts were, we can be for all practical purposes sure that John Brawner was the biological father of Richard Ferguson. Since the source of CTS4089 introduced into Ferguson family undoubtedly was the Brawner line of the said John, the implied NPE could happen neither earlier since John was born in Maryland nor later since he and his Triplett wife moved to Pittsylvania County, Virginia, where they died, while the Fergusons went south to North Carolina. Thus, the only place where the Brawners and Fergusons came to contact to allow the NPE was the Prince William County, Virginia.