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Archiver > DNA-R1B1C7 > 2011-06 > 1309184531


From: Charles Cain <>
Subject: Re: [R-M222] O'Cathain, off modal matches, 448=16
Date: Mon, 27 Jun 2011 10:22:11 -0400
References: <000001cc34b3$90b20d40$b21627c0$@com>
In-Reply-To: <000001cc34b3$90b20d40$b21627c0$@com>


Sandy

Mostly in agreement here.

You said:

"So the more off-modal (rare) matches
you have with someone, the lower the expected TMRCA for a given GD."

This seems reasonable on first reading. However, if the marker is
stable (as 448 is), and a particular STR non-modal value at that
marker is rare (as it is likely to be), it will persist and may reach
back some way in time (as SNPs usually do).


If a panel of rare STR values exist at stable sites, could it not be
true that the panel may have developed further back in time than
standard procedures measure?

I will have to think about this.

Charles




Quoting Sandy Paterson <>:

> Two Points here. Firstly, Ken Nordtvedt's paper at
>
> http://www.jogg.info/42/files/Nordtvedt.htm
>
>
> is relevant. Essentially, he explains that matches that appear to be close,
> are actually about twice as distant as traditional TMRCA estimation suggests
> they are. Further, traditional methods of estimation exaggerate the TMRCA
> for more distant matches. I couldn't find what he means by traditional
> methods, but I did manage to follow most of his reasoning.
>
> So we may be seeing a little of that here.
>
> Secondly, (as you know), rare matches are more important than common matches
> (as you've pointed out with DYS448). So the more off-modal (rare) matches
> you have with someone, the lower the expected TMRCA for a given GD.
>
> In our case, we have six off-modal matches, at
>
> DYS439=13
> DYS570=18
> DYS710=34
> DYS715=23
> DYS513=14
> DYS643=11
>
> In addition, we have what I've come to term a 'directional match', in that
> we are both 14+ at DYS=446 (modal value 13). I am 15, you are 14.
>
> I think it's going to be interesting seeing whether the 23,14,11 at
> DYS715,513,643 is present in Cain and variants with DYS446=13. If not, that
> will give us a useful clue as to kinship. If it is present, that knowledge
> should help in trying to work out the order in which the mutations most
> likely occurred.
>
>
> Sandy
>
>
> -----Original Message-----
> From:
> [mailto:] On Behalf Of Charles Cain
> Sent: 26 June 2011 19:25
> To:
> Subject: [R-M222] O'Cathain, off modal matches, 448=16
>
> Looking at Sandy's chart, I am struck by how "unrelated" in GD terms
> we all are although that is a relative concept I suppose. Under each
> new name on the chart, the most closely related subject almost always
> jumps to a GD of over 10 with around 15 being the most common (too
> lazy to compute the average "jump"). The value of off-modal markers
> becomes obvious from this chart.
>
> In my own case, the jump in GD is only 4 to a Kane. We have compared
> notes because I noticed several years ago the we share an off-modal
> match at marker 448. In M222 this marker is uniformly 18 repeats.
> However, 4 "Cain/Kanes" have 448=16, extremely rare and not shared (to
> my knowledge) by anyone else.
>
> In contacting these people, one 25 marker Cain (GD=0), turned out to
> be related on paper back to a common ancestor just before 1800. If
> fact, the father of this common ancestor was at Valley Forge in the
> Revolutionary War, always an interesting fact to turn up. Also, his (
> Mr. Valley Forge's) father was the likely immigrant from Ireland to
> New Jersey in 1740. So DNA helps!
>
> Another 448=16 colleague (the other Kane/Cain with 111 marker results)
> is unlikely to be related before the 1740 date mentioned above. This
> is based on lack of common spelling of our last name, different family
> religious affiliations, and different arrival times of our immigrant
> ancestors. So we are related only before 1740.
>
> On one of the DNA tree charts (I think based on Bill Howard's
> computations), we reach a common branch at about RCC=9, or some 400
> years ago, or around 1600. This is entirely consistent with what is
> likely true from other considerations.
>
> Moreover, both of us (Cain and Kane) trace back to the next branching
> of the "RCC tree" at around RCC=22, or some 950 years. If Bill
> Howard's computations are sensitive to rarity of mutations at each
> site, that is a good guess for when the 448 =16 mutation (from 448=18)
> occurred. If true, I am related to no other O'Cathain with 448=18
> after the year AD 1000. That seems like a useful piece of data.
>
> In that regard, if you want to know who to contact regarding possible
> common ancestors, look at rare off-modal matches. I has worked for my
> 448=16 colleagues and myself.
>
> Bill Howard may want to comment on my use of his data in the above
> exercise...particularly my use of his data to "estimate" when the
> 448=16 mutation occurred.
>
> Charles
>
>
>
>
> R1b1c7 Research and Links:
>
> http://clanmaclochlainn.com/R1b1c7/
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>
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