Michael Cooley's Genetic Genealogy Blog GEN • GEN
13 April 2018

Come On Baby, Light My Fire

CF09 is one of the largest and more mysterious groups of the Cooley DNA Project. It's the only group, for example, that has Cooleys and Coleys in more or less equal numbers. Although at least three members are descended from James Cooley (1758-1834) and Penelope Gargus (a fact that will benefit our research), most of the lineages have come to screeching halts for their respective researchers. But that the members are of the same family (in the larger sense of the word), is not doubted: The STRs closely match one another and the ancestors are roughly from the same region — Virginia, North Carolina, and Tennessee. I've long wanted to see advanced SNP testing so that we can start to sort the group out. Now that it's here, I'm all lit up. But anyone who has followed the progress with Cooley group CF02 knows that it takes time and that the science of genetic genealogy is still in early development. A Y-DNA groups' first step is gathering similar STRs. CF09 is now embarking on the second leg of the journey.

The first thing to notice about the following diagram is CF09's proximity to CF02 (Benjamin Cooley of Springfield, et al). But the great-grand-daddy of the bunch, Y15926, is believed to have lived about 3,000 years ago! One of two things can account for the same name: that the arbitrariness of surname assignment simply struck twice in the same ancient population, or Y15926, the man who introduced the mutation to his lineage, didn't live as nearly as long ago as estimated. I'm betting on the first scenario. In either case, there's no mistake about it: despite the similarity among the STRs, CF02 and CF09 were anciently related. It's merely a myth, once conjured up by a hopeful but inexperienced genealogist of years past, that James Cooley was descended from the Springfield, Massachusetts Cooleys.

The next thing to notice about the diagram is that the tree mirrors actual familial descent. But the branching occurred long before any records existed. The Y chromosome, however, is a storehouse of genetic artifacts from our paternal ancestors. BY3233, middle left, passed his Y genetic makeup to his sons whole hog. What he had on his Y chromosome, James Cooley had, and what A12020 had — on the right — Benjamin Cooley had. In fact, it's not genealogical information that allows us to see the split represented on the lower right of the graphic. DNA informs us that the family branched in that way — as families, by the way, tend to do. Both A12022 and A20349 descended from A12020, whether we know the actual names of the bearers of those SNPs or not. Thus, the diagram at the top of The Re-Emergence of the Goshen Cooleys represents a very real family tree. We just have a lot of blanks to fill out. Nevertheless, we do know that James M Cooley (on the Goshen Cooley tree) was a cousin of some degree to Abraham Cooley, both descended from A20349, and that they were distant cousins of Benjamin.

SNPs trees like the above can be vast and immense. The world-wide Y-SNP tree, which cannot possibly be fully represented in a single graphic, has tens of thousands of known SNPs, with hundreds of thousands, perhaps millions, yet to be discerned. A wider view of the descendants of P312 alone, several degrees upstream of DF83, can be explored at The Big Tree. But apart from finding our place in this bigger picture, how can this information enhance our research?

Our Big Y tester, kit #B12855, has nine novel SNP mutations (single-point changes from either A, C, T, or G to one of the others). These mutations, to date, are known to exist only on his Y chromosome and are presently represented only on the above tree. Of course, any sons he might have would also have them, as would his father, the person from whom his Y chromosome was inherited. Each of the tiny changes crept into the lineage going back through his paternal great grandfather, back through James Cooley, then BY3233, Y15926, and all the way to DF83 and beyond. It's much like following a bread crumb trail. And should the tester's patrilineage continue forward another thousand years, more SNPs will accumulate among his male Cooley descendants.

What is not novel is shared

All but the nine stated SNPs — numbering into the hundreds, even thousands — are shared among the tester's ancient cousins and their descendants. We know that he belongs to the BY3233 because he has those SNPs, as do the Nobles and Barnums. He doesn't have the A11786 SNP so he doesn't share that descent with the CF02 Cooleys. That's what the Big Y is all about: Finding matching SNPs between other testers, evaluating the degree of relationship based on that knowledge, and recording what's left over — those nine novel SNPs. That's now a done deal. We know the major branch to CF09 Cooleys came from. To what degree can we describe the new branch?

The question du jour, then, the one that allows us to start to make sense of this, is With whom does our tester share the nine Cooley/Gargus SNPs? Which number of them (seven? eight?) was James himself born with — those that were passed to all his male Cooley descendants? And which of the nine (one? two? three?) are truly novel, or private, to the tester's lineage from James? Just as the Nobles, Barnums, and Cooleys share the six SNPs in the BY3233 block, X number of these nine SNPs are shared among James's descendant. Finding those SNPs will provide an identifiable DNA print for James's descendants. And because we know when James lived, we can place him on a timeline. Likewise, his DNA print — the SNPs themselves — can be placed on that timeline. James's DNA print is not quite synonymous with his name but it can help describe his relationship to others: The degree of mismatching another has that print — the genetic distance (GD) — will tell us something about the degree of cousinship.

Test Options

There are two surefire ways to discover that print: other members can test the nine SNPs separately or order a Big Y. The undiscounted cost of a Big Y ($575) is prohibitive for most members, although it is an apt reward for what the test accomplishes, which is principally about SNP discovery.1 The test wends it way, via chemical reactions that I don't understand (I'm neither a geneticist nor a chemist), through a jungle of the tens of millions letters (A, C, T, and G) on the Y chromosome. It examines about ten million of them, then collects and returns home with (typically) a handful to several dozen mutations never before seen — much like a foraging expedition to the Galapagos. (Well, not exactly.) Once these new, novel SNPs are matched to another tester, they'll be rewarded with their own residence on the SNP tree.

But it's also possible to test for specific SNPs that are already known, even if not yet placed on the SNP tree. These nine SNPs can be tested at FTDNA for $39 each and at yseq.net for $18 a piece. Although the latter requires a new sample for yseq's lab, I highly recommend the company to those who prefer not going the more expensive route. And though SNP testing will not find new SNPs — only the Big Y or a comparable test can do that — your tentative place on the tree can be discovered.

Here are the SNPs that need to be tested. If a tester has all of them, he's closely related to our Big Y tester. The fewer the matches, the more distant the relationship.

A21489, A21490, A21492, A21493, A21494, A21495, A21496, A21498, and A21961

DNA Group Prints

Knowing which of the nine SNPs James was born with will give us an anchor by which we can evaluate future results. For example, we have a specific DNA fingerprint for group CF01, John Cooley (c1738-1811) of Stokes County, North Carolina (YP4491, YP4492, YP4493, and YP4494). If a future tester has all but one of those SNPs, we know that he is not descended from John but from a collateral line — a uncle or cousin of John's. It's a similar scenario for anyone who lacks any of the group CF02 Benjamin SNPs (A12022, A12024, and Y23835). And two descendants of John A Cooley (1756-1794) of Darlington County, South Carolina (CF07) share ten SNPs, which provides a specific genetic portrait of that man. Any deviation from that by a new tester will provide a hint as to the degree of relationship among the testers and establish a new branch on the SNP tree — and that will mirror the genealogical realities.

On the other hand, group CF04 has only one advanced SNP tester for a descendant of Robert Cooley (1754-1794), and the six new SNPs found for him are still considered novel.2 Until a second tester comes along, we will not have a genetic definition for Robert. We know only that the six mutations came into the line sometime between the tester's birth and the emergence of the parent haplogroup, R-YP4945, about 1400 years ago. Until those SNPs begin to parse down, we're unable to grow that branch of the SNP tree.

Additional Big Y's and individual SNP testing has allowed the CF02 group, which has origins in and around Tring, England, to break up into at least three genetically identifiable groups, as outlined in articles 41 and 47. A fourth group, the descendants of Samuell Coley (1614-1684) of Milford, Connecticut, is yet to be defined.3 CF09 might turn out to be not as robust as CF02, but SNP comparisons will allow us to draw our first tentative tree and assign members to it. Will we be able to distinguish between the Cooleys and the Coleys? How similar will the Y-DNA prints be between James Cooley and Andrew Drury Cooley, for whom we have at least two testers? And can it be that CF09 is descended from Captain Abraham Cowley (1691-1779), or will he be proved to be of a collateral line?

And so...

If the Cooleys and Coleys of the area and era were tightly related, we might not find a big difference among the SNPs. Since we don't yet know the truth of it, this makes additional Big Y testing somewhat a gamble, although it has certainly paid off for CF02. The yseq.net fee of $162 for nine SNPs, however, is a reasonable bet. We can't really speculate about the results, but considering an average mutation rate of about 144 years for each SNP, these nine might have emerged over a period of about 1300 years. Given that, a good portion of the SNPs (and their respective men) were "born" before the advent of surnames, well outside what we could reasonably call "Cooley/Gargus." And we might expect a genetic distance (GD) of no more than a couple of SNPs among CF09 testers. It depends on how distantly related the group members are to one another, which is something we presently have no notion about. In all likelihood, the first version of the Cooley/Gargus SNP block will amount to between six to eight SNPs. Here are some possible outcomes:

"'Round, 'round the wheel goes..."

The data can tell us virtually anything. But it's testing like this that has allowed the genetic genealogy community to create accurate trees that have been reordered out of the tens of thousands of SNP mutations. In any event, more data means better data — and better data lights my fire — and insures future updates.

1 Similar testing can be done at fullgenomes.com and at yseq.net, although the Big Y remains the most cost effective.

2 Novel SNPs are generally not given a name until a match appears. But I tend to name them through yseq.net once they show up in the groups I admin. It provides a human-readable name, as opposed to referencing them by position number, ancestral allele, and derived allele. For example, A21489 represents a mutation of A to G on position 10027821 of the Y chromosome — and that's a mouthful.

3 The CF02 STR results initially convinced me of the likeliness that Samuell and Benjamin were brothers. However, our single Samuell tester is negative for all three Benjamin SNPs. That fact plus the consideration that Samuell's STRs have a larger than average genetic distance among the Benjamin testers indicates they were probably remote cousins, although certainly of the same extended family.