I've written extensively on this blog about the Y chromosome and its unique pattern of inheritance. Suffice to say for the purposes of this article that only men have one and they inherited it whole hog from their fathers. Because the same pattern is manifested generation after generation, this informs us that any man's Y is the same as his paternal 8th great-grandfather; that and beyond. And, as it so happens, the surname generally passes in the same fashion. There's a big difference, though. Genetic inheritance is a biological fact. Surname inheritance is a social convention.
Once it sinks in, this becomes a remarkable fact. And because a lineage will periodically gain a mutation on the Y, we can map the chromosome into collateral branches, each new marker passing through the generations of the collateral line. These branches can occur as often as every 150 years or less, but discovering them at that frequency is a challenge. It all depends on who has tested.
Here's a good example of the successful detection of branching from the CF02 group of the Cooley DNA Project (not related to me). This family originated in or near the Hertfordshire village of Tring, England around or before the sixteenth century. The Cooley DNA Project initially assumed that everyone in the group descended from an early immigrant to Massachusetts named Benjamin Cooley (1615-1685). But advanced Y-DNA testing has revealed that there are at least four collateral lines:1
The markers listed below the horizontal line, from an as-yet unidentified Cooley, would have emerged in the last few hundred years. Because good public records exist for the Cooleys in that region for the 16th and 17th centuries, this new genetic information will be helpful to genealogists.
The Cooley Project is medium-sized. In comparison, the Fisk DNA
Project is quite small. At this writing, there are eighteen
Perhaps trying to determine the descent from Symond to Richard Fisk and others has been rendered somewhat academic in view of the overall genetic match. But, as shown in the Cooley diagram, a great deal can be learned from further testing. For example, two testers in Fisk-02 have delineated their lineages from Symond, which I've rendered, if rather crudely, at Patrilineal Descendants of Symond Fiske (1399-1464) of County Suffolk. Here's an abbreviated form.
The Short Tandem Repeat (STR) markers we see on the results page are good for placing testers into general groups. They're not good for delineating collateral lineages, such as we see in the Cooley diagram. For that, researchers have found hundreds of thousands of single point mutations, known as SNPs, which sit in highly stable regions of DNA.2 They're so stable, that some SNPs are suspected to have passed through the male line for more than 300,000 years, which is, by some estimates, since before the emergence of modern man!
These advanced markers are used to define haplogroups, groups of markers that are inherited together. The Fisk-01 group tested in 2013 to belong to haplogroup I-P37. The emergence of haplogroup "I" (the first part of that symbol) occurred about 30,000 years ago and, the SNP P37 (the second part of I-P37) is deemed to be in the neighborhood of 20,000 years old. This, of course, does little to further the genealogical research.
Fisk-02 has had only one advanced SNP test back in 2005. That SNP, R-P25, is not only equally ancient to I-P37, it has been deleted from the database because it has been found to exist in an unstable region of the Y chromosome.3 Even if we were to accept it, there are dozens of families, including my Wrights and countless more, that descend from the same marker.
If Geoffrey and William were indeed brothers, as the traditional ancestry suggests, they would have received exactly the same markers from Symond. Those matching markers would represent a specific Y-DNA print unique Symond. For the sake of illustration, let's group all the hundreds, perhaps thousands, of markers as "Haplogroup Symond." But in the eighteen and more generations since, additional markers have crept into both lineages. Let's call the first three to have emerged in Geoffrey's line as A, B, and C, and the first three in William's line as D, E, and F.
Should any of the representatives of these lineages do advanced testing, there is no telling how many "private" SNPs would be discovered. For the Big Y-500 testing of recent years, I'd typically expect between six and ten. But the Y-700 is looking at about 50 percent more of the sample and is yielding greater numbers.
The lesson is, I think, reasonably clear. A typical 37-marker test will put the tester in a corresponding group, in this case, the Symond Fisk group of testers. If the tester were to do advanced SNP testing and found to have a "B," he descends from Geoffrey; if an "F" is found, the tester is of the William group. Of course, this a straight-forward and fictional example. It can become far more complex.
In 1896, Frederick Pierce published Fiske and Fisk Family, which includes numerous lineages, primarily of New England stock, down to the late nineteenth century. Of course, the general expectations that a genealogy be well-cited wasn't encouraged then to the extent it is today and contemporary researchers suffer from the ill-effects of sloppy work. And, certainly, the Victorians didn't have the benefit of genetic testing. Certainly not everything that Pierce compiled for the book is wholly accurate, but that so many people claim descent from Symond and can now back it with DNA evidence is a testament to the work. It's a gift to modern Fisks that such a tome exists at all. Through it, we have access to a degree of reliable paper evidence, which can only enhance our research.
That a genetic lineage has any chance of being verified by a paper trail for twenty or more generations is a relatively rare opportunity. We have the opportunity to ask, Are you from Geoffrey, William, or another brother? As it now stands, only the Shadow knows. But we now have the means with which to illuminate that little corner of history.
I'm happy to answer any and all questions about this and genetic genealogy in general.
1. The results for advanced Y-DNA testing for a descendant of Samuell's is due in July 2019.
2. SNP is the acronym for Single Nucleotide Polymorphisms. A nucleotide is simply a molecule, the four kinds represented by the letters A, C, T, and G. A polymorphism is a mutation.
3. Susan M.Adams, Turi E.King, Elena Bosch, Mark A. Jobling, "The case of the unreliable SNP: Recurrent back-mutation of Y-chromosomal marker P25 through gene conversion," Forensic Science International 159, 14-20, h://www.sciencedirect.com/science/article/pii/S0379073805003701?via%3Dihub
4. Frederick Clofton Pierce, Fiske and Fisk Family: Being the Record of the Descendants of Symond Fiske, Lord of the Manor of Stadhaugh, Suffolk County, England, from the time of Henry IV. to Date, including all the American Members of the Family (Chicago: W B Conkey Co, 1896).