ADVANCED Y-DNA TESTING
FOR THE ACREE ONE-NAME STUDY

by Charles Acree

(published in the Journal of One-Name Studies, July-September 2017)

The Acree One-Name Study that I administer is closely associated with the Acree Surname DNA Project that I initiated a decade ago, which compares men’s Y-chromosome ("Y-DNA") test results to validate patrilineal research and advance our understanding of the history and geographic distribution of our family name.

During the past two years, our project has been replacing conventional Short Tandem Repeat ("Y-STR") Y-DNA testing with Single Nucleotide Polymorphism ("Y-SNP") testing for most of our comparative efforts. This transition has greatly reduced the cost of testing after recovering an acceptable initial investment. Equally important, it has eliminated ambiguity in our comparisons.

DNA surname projects have customarily employed Y-SNPs merely to assign participants to ancient patrilineal haplogroups that Y-SNPs define and further into subclades forming hierarchical trees having branches that extend into the classical era, with speculative centuries and locations of origin. The advent of next-generation-sequencing ("NGS") technology a few years ago has brought radical change. It has resulted in the discovery of thousands of these randomly-occurring mutations, metaphorical twigs that originated in medieval and modern times - within the past few centuries, our researched lineages, and even our own births.

This deluge has made Y-SNPs genealogically relevant. A persistent disadvantage of Y-STR testing has been that it requires laborious comparisons of lengthy strings of differing marker totals (called "haplotypes") that can be indeterminate, even when a maximum number of markers are compared at substantial cost. Y-SNP testing, in dramatic contrast, permits unambiguous comparison of sequential, cumulative mutations. It is definitive, overruling any apparent Y-STR-based contradictions that may arise.

The Acree DNA Project

During the past ten years, our project, which now tests primarily at the Family Tree DNA (FTDNA) firm, has found that most Acrees living in the U.S. descend from the same immigrant to Colonial Virginia that I do and that nearly all the rest descend from a contemporary immigrant to Maryland. We have been unable to identify the European parents of these two progenitors, but family lore and Y-SNP testing indicate that both were descendants of families who lived in the English-Scottish border area. Our name clearly had multiple origins in the U.K., with numerous spelling variations, as surnames evolved centuries ago. Surprisingly, Y-SNP testing has revealed that the most recent common ancestor ("MRCA") of our two major progenitors lived in pre-historic times in central Europe, before the British Isles were significantly populated.

This article focuses on our primary progenitor, William Acre (c.1710-c.1767) of Hanover County, Virginia, who spelled his name with a single "e" and had five sons - William Jr., John Sr. (my ancestor), Abraham, Joshua, and Isaac. Y-STR testing has confirmed that forty-five of our current seventy-five participants descend from his sons as "Virginia Acrees." We all share the same haplotype, with insignificant differences.

Early Y-SNP Testing

For several years, our project knew little about our prehistoric haplogroups and the Y-SNPs that define them. FTDNA predicted that we belong to M269, a massive subclade of R1b, the most common haplogroup in western Europe. Some of us learned from basic testing that we belong to its descending subclade Z159, and that the series of numerous Y-SNPs that we have accumulated through the millennia has proceeded through these prominent Y-SNPs:

M269 > L11 > U106 > L48 > L47 > Z159

In 2014 I took the "Chromo2" Y-SNP panel test offered by the BritainsDNA firm, with another Virginia Acree and a non-Acree acquaintance who evidenced a reasonably-close Y-STR match with us that didn’t quite meet FTDNA’s marker thresholds at any level. We learned that I and the other Acree possessed the relatively new-found Y-SNP S6915, believed to have originated over two thousand years ago, while the non-Acree did not. We added it to our series:

M269 >>>>>> Z159 > S6915

It was the first Y-SNP that clearly differentiated Virginia Acrees from a nearly-matching non-Acree. To achieve further separation, we needed to find pertinent Y-SNPs that descend from S6915, but none yet appeared in established trees. Panels such as those offered by BritainsDNA and FTDNA are capable only of identifying Y-SNPs that originated long ago and are consequently shared by numerous living men. We wanted to take advantage of NGS technology, which can identify Y-SNPs born more recently and are thus less frequently shared. We selected FTDNA’s new "Big-Y" test for this purpose.

We perceived that it was important to compare the new YSNPs we hoped to discover with those of a non-Acree whose Y-STR results matched Virginia Acrees more closely, but not too close. A man with the surname Brown fit that requirement quite well. He had joined our project as a result of sharing our distinguishing haplotype, with differences that fell barely within FTDNA’s thresholds at 37, 67, and 111 markers at genetic distances of 2, 5, and 8 respectively. In pursuit of mutual goals, Brown and I agreed to take the Big-Y test together.

Big-Y Test Results

When it posted our Big-Y results in early 2015, FTDNA unsurprisingly identified Brown as my closest match and me as his. It displayed a list of Y-SNPs for each of us that included "known Y-SNPs," meaning those that are widely shared by others and already appear in its growing haplogroup tree. Additionally, it displayed a far shorter list of "novel variants" for each of us, which did not appear in its tree. Comparative lists displayed novel variants that we shared, those that were unique to me, and those that were unique to Brown.

At the time, FTDNA considered S6915 to be "novel," rather than "known." Heeding advice from volunteer administrators of the FTDNA-sponsored U106 haplogroup project that I had joined, I forwarded my raw test results to them for more penetrating analysis and sent those results also to the Full Genome Corporation (FGC) for additional analysis.

These independent analyses refined FTDNA’s posted results by identifying Y-SNPs that were truly new (originating after S6915) and dismissed low-quality Y-SNPs that were of questionable stability or independent testability.

They clarified that, beyond S6915, our Big-Y tests added to our series eleven Y-SNPs, of unknown order, that Brown and I share:

M269 >>>>>> Z159 > S6915 > 11 shared Y-SNPs with Brown

More tellingly, they clarified that the tests identified three new Y-SNPs for me and two for Brown.

Subsequent YSEQ Testing

Now that we had isolated three mutations that differentiated Virginia Acrees from a closely matching non-Acree, we could test further for them at the YSEQ firm, which offers individual Y-SNP testing at little cost. YSEQ named the three A2154, A2155, and A2156 (without implying order), using its "A" prefix. I convinced a half-dozen Virginia Acrees who had already confirmed their lineages through Y-STR testing to test additionally at YSEQ for possession of these Y-SNPs on behalf of our project. Since then, another half-dozen Virginia Acrees have tested there, further validating our initial findings and saving money.

When tested for A2156, all Virginia Acrees have been found positive for it, indicating that it was the first Y-SNP to originate following the birth of the unknown Acree/Brown MRCA. In view of the generality that the Big-Y finds a new Y-SNP, on average, every four generations within a lineage, A2156 must have originated in William Acree himself or in one of his near-term patrilineal ancestors. It could therefore be used to confirm his descendants, satisfying our goal of developing an alternative to Y-STR testing. Our Virginia-Acree Y-SNP series became:

M269 >>>>>>Z159 > S6915 > 11 shared Y-SNPs with Brown > A2156

When tested for A2155, only descendants of William’s son, John Sr. (my 4x great-grandfather) have been found positive for it. It could therefore be used to confirm descendants in his branch. It must have originated precisely in John Sr.’s own birth. The more restrictive Y-SNP series for his descendants is:

M269 >>>>>>Z159 > S6915 > 11 shared Y-SNPs with Brown > A2156 > A2155

When tested for A2154, only I and a first cousin have been found positive for it, indicating that it must have originated in our mutual grandfather or in an earlier member of our line born after John Sr. Our more exclusive Y-SNP series is:

M269 >>>>>>Z159 > S6915 > 11 shared Y-SNPs with Brown > A2156 > A2155 > A2154

Further Testing

Following this gratifying success, we attempted to find a Y-SNP that would differentiate descendants of William Jr., who heads a Virginia Acree branch larger than that of his brother, John Sr. One of my seventh cousins who descends from him took the Big-Y test and we tested other descendants for the two Y-SNPs discovered. This time we were not so fortunate. It turned out that both of his new Y-SNPs originated in my seventh cousin’s line after William Jr.’s birth, no identifying Y-SNP having been born in William Jr. himself.

We did succeed further, however, in isolating two Y-SNPs for which descendants of our second major Acree progenitor, who immigrated to Colonial Maryland, can henceforth test to verify descent from him. Two Y-SNPs are required in this case because we do not yet know which of them performs differentiation. We accomplished this with the serious disadvantage of having a far smaller matching group to test, consisting of only four descendants. Yet, it validated our methodology. If a new project participant does not know which of the two Acree progenitors was his, he can find out by testing inexpensively for these two Y-SNPs and for A2156.

Our strategy can be used by any ONS having an associated Y-DNA surname study at FTDNA. It is first essential to find two men who barely match each other in their Y-STR comparisons - one who descends from an outstanding progenitor and the other, presumably with a different surname, who does not. They must take Big-Y tests to isolate Y-SNPs that the first possesses but the second lacks. Other descendants of the progenitor can then test for possession of the new-found YSNPs to identify those that are genealogically relevant and therefore capable of verifying descent. Independent analysis by administrators of the relevant haplogroup project and/or FGC may be needed, but FTDNA has been continually improving its own Big-Y matching capabilities.

If you are an Acree seeking confirmation or extension of your paternal line, please consider participation in the:

Link to Acree Surname DNA Project

Click on the above link to connect or return to the explanatory project page.
Please direct questions to the E-MAILaddress there.