In the July-September 2019 issue of this Journal, John A. Creer discussed the incidence of "Non-Paternal Events" ("NPEs" - misattributed paternity) in the patrilineal lineages of men of Manx origin. He discovered through Y-DNA testing that they exhibited an NPE incidence rate of approximately 0.4% per generation - less than the average 1-2% rate that is often cited.
He calculated that if a 2% rate would be used in combination with an average generational length of twenty-seven years, there would be a 50% probability that an NPE has changed the surname of any patrilineal line extending 900 years into the past. Whatever time-span and multipliers are selected, those of us seeking to extend our lineages beyond a few hundred years cannot avoid the probability that hidden NPEs will render our well-researched findings inconclusive.
Several situations other than concealed infidelity have occasioned NPEs through the years, including unrecorded adoptions, but most NPEs have occurred within circumstances that were undisclosed at the time and undocumented for posterity. Through genealogical research alone, we can never appreciate the full extent to which NPEs have impacted our family histories. With the advent of Y-DNA testing, our inclination to disregard their indeterminate impact is injudicious.
The Acree One-Name Study, which is assisted by its companion Y-DNA Project, has determined that most Acrees living in the U.S., including me, descend from William Acre (c.1710-c.1767), who we believe immigrated to Virginia from the English-Scottish border area in the early eighteenth century. After many years of effort, we have been unable to determine his specific family origin.
I have been hoping that someday we will succeed in testing an Acree male living in the UK who matches us genetically, shedding light on that origin. The man matching us would presumably have a variant of our surname because the name Acree itself has been practically non-existent in the British Isles. Through the years, we've been grateful that several British men with Acree-variant names have tested with our project, but their Y-DNA results have differed considerably from ours. They generally belong to other ancient haplogroups and are thus related to us only in pre-historic times.
This experience has led us to believe that our surname grouping had multiple origins in the British Isles and to speculate that our genetic Acree line may have become extinct in Britain.
Beyond that, we have discovered through Y-DNA testing that we closely match several men having entirely different surnames - Brown, Collier, Hall, Peel, Wells and Willoughby, who are clearly associated genetically with our Acree line, rather than the lines of men sharing their own surnames (with the exception of identifiable relatives). Clinching their genetic match, they all possess a rare Y-DNA microallele that distinguishes our Acree line.
The nature of these non-Acree matches indicates that their individual relationships with us must have derived from NPEs that occurred several hundred years ago in Britain, rather than during the past three centuries in the U.S. Evidence for this assertion has been found through both genealogical research and advanced SNP (Single Nucleotide Polymorphism) Y-Chromosome (male) DNA testing, which has been gradually replacing conventional STR (Short Tandem Repeat) Y-DNA testing, as I discussed in the July-September 2017 issue of this Journal . Y-SNP testing is not only more definitive than Y-STR testing. In contrast to Y-STR marker values, Y-SNP mutations are hierarchical. They originate sequentially and cumulatively. As a result, approximate dates of origin are being progressively applied to them.
From those applied dates and the possession of certain Y-SNPs by men testing for them, it is apparent that the above non-Acree lines separated from our Acree line sometime between c.1300 AD, when the Y-SNP R-BY3313 that they all share with the Acrees originated, and c.1600 AD, when our Acree line acquired its distinctive Y-SNP R-A2156.
That perspective is from an Acree-centric point of view. It assumes that Acrees, through NPEs, intruded upon these non-Acrees' individual ancestral lines, possibly as informal adoptees, and then, as adults, had families of their own who used the non-Acree names of the adoptive parents.
There is really no way of knowing the specific ways in which the non-Acree surnames became associated genetically with ours or with each other. Any one of them may have been the "original" surname with which we and the others became related through NPEs. We may even all go back to a different surname that was adopted in the 14th century, when surnames became common. The fact that the non-Acrees individually have fewer DNA matches than we Acrees do with each other implies that an Acree-centric viewpoint is valid, but insufficient testing has been accomplished to support that conjecture.
Drastic "surname hijacking" occurs when an NPE completely takes over a genetic line from the founding surname of that line, while the founding line itself dies out. The original Acree line, however it began, may have been hijacked at some point by an NPE from an entirely different family. Or our Acree line may actually descend from another family line that we Acrees hijacked. Numerous scenarios are conceivable.
I suggest that any surname study that extends deep into the past and has accumulated abundant Y-DNA testing detail is likely to encounter puzzling associations such as ours, where extraneous surnames, involving occasional NPEs, complicate an otherwise straightforward researched lineage.
We can all expect that the personal surname lines that we have inherited will go extinct eventually, as so many have, through lack of offspring or "daughtering out" - one branch at a time. I am impressed by the tenuous situation that exists within my own Acree branch, as I contemplate the fact that my great-grandson is the only one capable of perpetuating our Acree line among the numerous descendants of my patrilineal great-great-grandfather.