by Phillip G. Goff, GGFA Director of Genetic Genealogy
For families whose paper trail grows cold somewhere in the colonial South of the USA, Y-DNA testing has become one of genealogy’s most powerful torches. The Big Y-700 test offered by Family Tree DNA takes that torch and multiplies its brightness a hundredfold — scanning more than 700 short tandem repeat (STR) markers alongside tens of thousands of single-nucleotide polymorphism (SNP) positions on the Y chromosome. For descendants of John Goff born ca. 1717 and who lived in Duplin County, North Carolina, the results have been transformative.
What Big Y-700 actually does
Traditional Y-DNA tests measure 37, 67, or 111 STR markers — useful for connecting cousins, but limited for separating branches or pinpointing where in a family tree a new line diverges. Big Y-700 goes further by reading the entire single-copy region of the Y chromosome, identifying private SNPs that become permanent generational waypoints. When two men share a newly discovered SNP, researchers can calculate with remarkable precision when their common male-line ancestor lived. In the Goff / Gough project, the defining haplogroup R-BY67755 already anchors all tested descendants to a single patrilineal origin — and new downstream SNPs are beginning to distinguish the major branches.
What changed between February and April 2026
A new Big Y 700 result was received in April 2026, updating the genetic tree from February 2026. The April diagram identifies YSTR DYS464d = 18 as a significant marker. This groups a large cluster of descendants, including those of Lewis Goff b. 1786 NC, William R. Gough b. 1809 KY and William Gough b. 1830 AL into a clearly defined sub-branch that was previously invisible. In February, these same men sat in an undifferentiated and disconnected block beneath William Goff 1761 NC. The new SNP effectively slices the William 1761 branch in two, separating the Lewis line from other sons.
A second notable development is the appearance of a confirmed YSNP = 15994845 on the Dempsey Goff 1758 line (left-hand branch), added directly to Dempsey’s node in the April chart. In February, this SNP appeared only in the deeper Kit 153448 results box. Elevating it upward confirms that this variant is a reliable marker for the entire Dempsey descent group — a meaningful promotion that helps researchers quickly classify new testers.
The April diagram also introduces autosomal DNA correlation data, with two atDNA Match annotations (61 cM and 41 cM) linking a female descendant and another individual into the William Goff 1825 MS sub-cluster. Autosomal resultscan help to triangulate relationships that Y-DNA alone cannot resolve.
Why this matters for your research
Every new Big Y-700 tester in this project adds potential resolution. Untested lines — including several marked “Private” in both diagrams — represent blank spaces that a single kit could illuminate. If your Goff, Gough, or phonetically similar surname traces to colonial North Carolina, Virginia, or Georgia, a Big Y-700 test could place your ancestor on this growing map with a precision no document search can match.
For more information, please check our DNA Family Groups pages or email me at dna@goff-gough.com. Each new participant helps to fill in the history of the Goff/Gough families.
Phillip Goff is the co-author, along with Roy L. Lockhart, of The Four Goff Brothers of Western Virginia. Since 2004, he has run the Goff/Gough Surname DNA Study, which today has about 400 participants.