Should I add Y chromosome information to support Irish origin of Darby Field?

Question

I am a direct descendent of Darby Field (see below) and have had Y-700 sequencing done at FamilyTreeDNA. A second direct descendent has also tested Y-67 at FamilyTreeDNA and is a good match to me. We are third cousins, as confirmed by both Y and autosomal sequencing.

My haplogroup, which is shared by one other Y-700 tester, is R-FTA98228. The other tester's surname is Conner and he has listed as his Paternal Earliest Known Ancestor: John O'Connor, bc 1595 - d 1652, Co. Kerry. This is right around the time that Darby presumably immigrated to North America (before 1636). 

The other haplogroups that have been identified that are related to R-FTA98228, R-FT67376 and R-BY110673, also have Irish surnames (Donoghue and Mahoney, respectively) as their Paternal Earliest Known Ancestor. Although the genealogy on these only extends back to the 1830's or so.

According to the Family Tree DNA "Age Estimate" (on the Scientific Details page) this haplogroup arose between 1171 - 1532 CE (68% confidence interval). That supports the theory that Darby Field's ancestors were in Ireland in the 16th century (and likely earlier) and NOT from England like the ancestors of [[Field-1907|Robert Field Sr (1613-1675)]] and most of the other Field Y-700 testers (https://www.familytreedna.com/public/Field?iframe=ycolorized).

Do we think that this is sufficient evidence to add a section to the Darby profile ==Irish Origins== and modify the ==Disputed Origins== section accordingly?

I will work on that section once I see if there are any objections here. I would also include the information about the anglicisation of the name Diarmaid to Darby.

My relationship to Darby:
Darby Field→Zachariah Field→Stephen Field→Stephen Field→Daniel Field→James Field→Daniel Field→Haskell Field→George Field→Chester Field→[living] Field→[me]Ken Field

Italics indicate relationships confirmed by autosomal DNA testing. In bold is the most recent common ancestor of the other Y-67 tester. Side question: would it be helpful for them to get Y-700 sequencing, or would that only confirm the same haplogroup? It seems to me that it would be much more valuable to find a more distant cousin.

Comments

Thanks to everyone for the support and the interesting discussion. I have done an extensive edit to the profile and added the new genetic evidence. Please take a look and send me a message if you spot anything that I missed or messed up.

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Looks good ken. I will probably do a little rearranging to align with PGM standard formatting. I also think we should emphasize that the strongest evidence that he was Irish is Winthrops contemporaneous reference to him as an Irishman.

Answer 1

Ken, I think that the full characterization of your Y-haplotree would be a very important aspect of, and go a long way toward, establishing the Irish origin of Darby Field.  I hope the following will help you in doing that.

Bill Woods's "Rule of Three" (https://www.facebook.com/groups/ftdna.big.y/) says that three Big Y-700 testers are needed (in addition to an original tester) to characterize (name, and determine the chronological order of, the SNPs of) a portion of a male line's haplotree: a close relative, a distant relative, and an intermediate relative.  "Close" means a brother, father/son, uncle/nephew, or 1st cousin of the initial tester.  How far away the "distant" relative is will determine the "resolution" of the haplotree, that is, what portion of the chronological series of SNPs in the tree will remain uncharacterized: if 7 generations or less, the chance of "full" characterization is good, but if 8 or more, it becomes increasingly less likely, using just the 3 additional testers.  The "intermediate" tester will be somewhere between the close and distant, but usually, because of the average frequency of Y-DNA mutations (roughly every 80 years on average), no closer to either than 3 generations.

Currently, you have your "distant" relative, Mr. Connor, whose relation to you appears to be at least 10 generations back, and your shared (distant) haplogroup has been identified.  You also have a semi-close relative, your 3rd cousin - though he has only taken the Y-67 test.  In order to identify your more recent haplogroups, (though probably not the most recent, as he's not quite close enough) he will need to upgrade his test to the Big Y level.  This is critically important.

Finding an additional (intermediate) cousin, somewhere in the 5th - 7th range if possible, and having him tested, will complete your "Rule of Three."

Your other two "related haplogroup" testers are probably part of your more distant family (with different surnames, probably quite a ways back).  Contacting these testers to find out if their haplotrees have been at least partially characterized, could also help in your quest to establish/confirm Darby Field's origins.

Comments

The ‘rule of three’ worked for me but the BLOCK TREE report indicated at least 18 SNPs needed to be resolved to find an indicative SNP for my MDCSA (most distant common surname ancestor) which was the aim of my BigY test. The SNP count down the left side of the BLOCK TREE report indicates cousin distance. Close cousins to resolve close SNPs and distant to resolve distant SNPs, each likely to introduce more PVs. It is a long process trying to find men who might test or waiting for them to appear as as a new match. Y-37 with the same surname puts them into your family, but BigY is needed to locate them accurately. Regrettably even Y-111 is not accurate enough.

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Yes, it's definitely a long process.  The comparison I've often heard is it's a marathon, not a sprint.  So, 18 SNPs, that could be over 1400 years - are you thinking that your surname goes that far back?

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Rumour has it that the tax man in Florence introduced ‘binomial’ names in around 1400 to increase the the tax take and the idea caught on. No suprises there. Mine appears to be derived from ‘ap’ or ‘son of’ Richard, maybe from the Prichards of Llancayach, in Wales in the 1500’s, so you never know. Given sufficient testers, it might even be proved. Currently MRCSA is FT32960 which, I’m told, appeared around 1050 CE, maybe in Wales, but with 7 SNPs between it and FT34773, there is plenty of room for other surnames to appear. We need more ‘like surname’ Welsh and Irish testers, so here is hoping the snails heard the marathon starters gun.

Edited to add that the point of my message was, for Ken and others who pass ‘the rule of three’, that resolution of their ancestral tree is still a very long way away. I have 7 matches, four close and three distant, so the first steps of the marathon  have been taken.

Answer 2

Ken, it's possible (but I think very unlikely) that your cousin could get a Y-700 result that doesn't match yours. It would be rather amazing if it turned up a different haplogroup.

IMHO, your analysis is pretty sound and my money would be on Darby being Irish. I think I'd remove the "disputed" in the section title because...is anyone actually arguing that Ireland isn't the more likely origin? At the same time, it still seems possible that he came to the New World from England and that his Irish heritage is longer ago, so I'd leave the sources that support it in the profile, maybe in something like an "alternate origin theory" section.

I guess the bottom line is, "No objections here."

Comments

I'm sorry, but it's virtually a certainty that testing Ken's third cousin will result in identifying at least one new haplgroup in his Y-haplotree.  (See my posted answer.)

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Can you refer me to a reliable source that supports that?

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If the average person has 175 third cousins, based on this statement on the R1b group's FTDNA website implies that the odds of a different terminal SNP would be somewhere around 1 in 75, maybe a little better. It seems likely that a few of his third cousins would have a different terminal SNP but pretty unlikely it would be that particular cousin.

https://www.familytreedna.com/groups/r-1b/faq#FTERMS:~:text=In%20Big%20Y%2C%20there%20is%20an%20SNP%20about%20one%20of%20every%20two%20and%20half%20generations%20(father%2Dson%20transmissions).

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My favorite general text on the subject is David Vance's "The Genealogist's Guide to Y-DNA Testing for Genetic Genealogy.  I'm looking for a reference that would address this specific point - hopefully I'll find one shortly - but in the mean time please consider this.

A new SNP mutation (i.e., a new "genetic generation") occurs roughly, on average, about every 80 years.  FTDNA's "Discover" feature estimates that Ken's R-FTA98228 haplogroup formed around 1350 CE, or roughly 650 years ago.  650 divided by 80 is about 8, so we would expect about 8 new SNPs to have have formed since R-FTA98228 occurred, meaning that there are likely 8 new haplogroups in his haplotree yet to be identified.

Ken and his 3rd cousin stopped sharing their haplotree when their 2nd great grandfather's two sons (Ken and his cousin's great grandfathers) were born - probably, very roughly, around 80 years (one genetic generation) before Ken and his cousin were born.   Therefore, Ken and his third cousin are very likely to share 7 of the as yet unnamed haplogroups.

Since SNPs are not named until at least two men are seen to share them, those 7 SNPs probably won't be named until Ken's cousin upgrades his Y-DNA test to Big Y - but once that happens, one of those newly named haplogroups will become Ken and his cousin's new "terminal" haplgroup.  This is just how Big Y DNA testing works.

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Y-DNA deals only with the direct paternal line, so the theoretical number of direct line male 3rd cousins, even in a very prolific family, would not be anywhere near 175.

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Well, I wasn't referring to 175 male line cousins but yes, it would be far fewer. But what I meant in my initial post was that it would be rather amazing if their haplogroups differed from each other. Based on your comment about 30 minutes ago, it seems we'd agree on that. If anything, they might find that one belongs to a subclade of the other. Yes?

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And my understanding is that determining a new subclade for one of them would require more testers. (edit: Ok, to be precise, it would require at least one more tester.)

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You're right. When the 3rd cousin upgrades his test, he and Ken will share the "revealed" haplogroup, but if and when Ken has a closer relative tested (brother, father, son, etc.), that last as-yet-unnamed SNP - a subclade of the earlier one - will be identified, and become his (and his closer relative's) terminal (no quotes) haplogroup.

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Great, thank you for helping me think through this. It looks like this paper shows a calculation of 83 years per SNP:

https://www.mdpi.com/2073-4425/12/6/862

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That's a great article - thanks!  That number has been floating around for quite a while, but this looks like a really rigorous re-evaluation of it.  It's important to remember though that this is a long-term average.  Mutations can occur pretty much any time, and the intervals between genetic generations can be anywhere from a few years to over a century.  So I don't feel too bad about using the rounded-off value of 80 years, at least for estimating spans of less than 10 generations.  (Doing the quick math is so much easier, and the difference between 10 generations at 80 years and 83 years is only 30 years - well within the variability between any two individual genetic generations.)

Answer 3

I'm sure the PGM Project would welcome those additions to the profile.  From what I've seen, typically those discussions are in a separate DNA section. But, since almost all PGM era immigrants were English, it might make sense to highlight Darby's Irish origins. The Disputed Origins section should mostly serve to discredit the misconception that there is evidence he was from Lincolnshire. The profile could be reformatted to have only a brief statement to that effect and then refer to a longer discussion in the Research Notes section. Hopefully, someone in Project Leadership will comment.

I don't have much experience with the BigY testing.  But since you have autosomal DNA also confirming your reliationship, it seems like having BigY results from your third cousin would only possibly identify more recent mutations, which isn't that useful.  I agree with your thought that finding a more distant cousin would be a better investment. To confidently assert the value of the DNA evidence for Darby, you need to get confirmation further back in your tree.  There are quite a few generations where theoretically an NPE of Irish origin could explain your results.