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Archiver > DNA-R1B1C7 > 2008-01 > 1200548288

Subject: [DNA-R1B1C7] Some Musings on R1b1c7
Date: Thu, 17 Jan 2008 00:38:08 EST

The Trinity Study.

The Trinity study, based on a sample of 59 surnames linked by pedigree to
Nial 'of the Nine Hostages' (d. 405 A.D. ), arrived at two different TMRCA
estimates; one was 1730 years ago, or about 277 A.D. The second estimate was
1,010 years ago (or about 997 A.D.). The team concluded the first estimate was
"at least consistent with an early medieval time frame." The second
suggested an origin predating the adoption of surnames in Ireland (generally beween
950 A.D. and 1100 or later). Of these 59 samples roughly half matched the IMH
modal or what is now called R1b1c7. The Trinity team suggested the non
matching samples were the result of "the cumulative consequence of nonpaternity
events and the induction into the clan structure of unrelated males. "

The Following surnames were involved in the 59 sample study.

(O’)Gallagher (12), (O’)Boyle (9), (O’)Doherty (5), O’Donnell (4), O’
(3), Cannon (3), Bradley (2), O’Reilly (2), Flynn (2), (Mc)Kee (2), Campbell
Devlin (1), Donnelly (1), Egan (1), Gormley (1), Hynes (1), McCaul
(1), McGovern (1), McLoughlin (1), McManus (1), McMenamin (1),
Molloy (1), O’Kane (1), O’Rourke (1), and Quinn (1).

Anyone familiar with Ui Neill surnames in Ireland will immediately recognize
many of these surnames. Most are either Cenel Conaill or Cenel Eoghain,
said to descend from two different sons of Nial 'of the Nine Hostages.' (d. 405
A.D.) Perhaps less well known is the fact that a group of these surnames
fall into the tribal designation of Connachta, who are not said to descend from
Nial in the pedigrees. Instead the pedigrees have them descend from brothers
of Nial, a genealogical statement few historians accept as historically
accurate. But the pedigrees do claim at least a genealogical link between the Ui
Neill (descendants of Nial) and the Connachta (descendants of Conn, an
earlier ancestor in the pedigree) and DNA appears to validate the claim.

Nowhere in their article does the Trinity team actually state that Nial 'of
the Nine Hostages' was the common ancestor of R1b1c7 in Ireland. They point
only to an "early medieval time frame" more or less consistent with the time
of Nial (but actually predating him by several centuries). Associating this
common ancestor with Nial is a leap the Trinity team did not make although
nearly everyone else has.

It's also important to point out that the Trinity study included only Irish
samples. In their article, they cited an earlier Capelli Y chromosome census
of the British Isles which featured a much reduced marker set and noted that
"The 6-STR IMH is virtually absent from much of Britain but reaches
frequencies of up to 7.3% (16.7% including likely one-step derivatives) in western
and central Scottish locations." The article did not mention that the Capelli
study also found a few similar haplotypes in Denmark and Norway. Attempting
to identify R1b1c7 from such a limited marker set is problematic at best.

The Trinity study therefore did not address the question of when R1b1c7
originated. It simply estimated the TRMCA of a sub-group called the Ui Neill in
Ireland (to which for accuracy's sake we must add the Connachta). They made
no attempt to to factor in Scottish or English R1b1c7 samples although they
were aware it existed.

Most of the leading DNA experts on the GEN-DNA list believe R1b1c7
originated in Ireland in the northwest. Or if not in the northwest at least in
Ireland. Estimates vary as to the TMRCA but John McEwen for one has stated it
could have been many thousands of years ago, as early as 3,000 BC. (which he
calls a conservative estimate). I have no idea what dataset John McEwen used in
his estimate but I'm sure it included a lot of Scottish samples (possibly his
R1bSTR19 cluster).

At a glance there seems to be quite a dichotomy between the estimates on
GEN-DNA and the Trinty estimates of 275 A.D. But perhaps they were looking at
different aspects of the same puzzle. The two estimates might not be so
incompatible after all.

Is this a possible explanation for the wildly varying dates given in the
Trinity study versus the opinions of DNA experts? That the Trinity study
considered only DNA samples from surnames alleged to be descendants of Nial or the
Connachta in Ireland and other estimates include the whole range of R1b1c7
from Ireland to Scotland? Would adding Scottish and English DNA to the surname
mix used by Trinity result in a different TMRCA for R1b1c7?

It might be an interesting experiment but I don't know how to conduct such a
test. The Trinity team stated they used Network.exe to estimate TMRCA for
their surnames. How did John McEwen arrive at his own estimates?

"The time to the most-recent common
ancestor (TMRCA) of this lineage was estimated
with the r statistic (Morral et al. 1994) in NETWORK,
with use of a mutation rate of 1 per 2,131 years for a
17-marker haplotype (Zhivotovsky et al. 2004)."

Under Time Estimates in Network, the following parameters are asked:

1 mutation every

20,180 [default] years

Then you are asked to select an ancestral node. What do you chose here?
The R1b1c7 modal? Or will any large node do?

Then you have to select descendant nodes.

To use this I assume you'd have to come up with a years figure based on 25
or 37 markers. Either that or restrict your markers to 17 to match the Trinity

Does anyone have any opinions on the validity of the time estimates
generated by Network.exe or how to establish the parameters used by the program?


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