Hi Gloria,
I finally got into GEDmatch.
We share a 5.4 centiMorgan segment on chromosome 22. GEDmatch says that's
714 SNPs. That's really, really small. We match those for one of two
reasons: Identical By Descent (IBD), or Identical By State (IBS)--meaning
by chance.
I'm not sure of the exact degree of our relationship. I'm 9 generations
from John. If you're 7 generations, we'd be 5th cousins twice removed.
That means that--at best--we'd share about 0.0122% of our autosomes.
According to a reference at the ISOGG website, 8th cousins--at about
0.000763%--share about 23,000 SNPs. I'm not good at math, but a very rough
calculation suggests that our shared SNPs might have been passed down from
a common ancestor of about 12 generations--or one of more than 4,000
people. Even if we could compare our complete ancestry over 12
generations, we couldn't begin to guess which one those 714 SNPs came
from. It could have been the Cooley line, but I'm guessing we have other
common lineages that far back.
The only way we could determine whether those SNPs came down through the
Cooleys would be to find multiple descendants having the same SNPs--and
then rule out all other possibilities.
Look at at this way: It's extremely likely that we both inherited some of
John's autosomal DNA. But John had about 3 billion base pairs. The notion
that we might have inherited the same 714 from him is unlikely.
We need to try to nudge Jim into testing. The two of you are a couple of
degrees closer and, I think, within the range of conventional prediction.
Or here's another idea...are either of your parents alive? If one or both
tested, you might be able to isolate which side of the family those SNPs
came from.
I've never been big on autosomal testing. It's kind of like sorting
through the grains of salt on a teaspoon. I got lucky in that an easily
identifiable 2nd cousin of my dad's--and her daughter, and her
granddaughter (three generations!)--tested. The pattern was striking. I
was able to provide them with information about a line they knew nothing
about. But when I asked for more information, they closed down the little
they were sharing. :(
Don has been exploring autosomal testing a lot longer than I have. Perhaps
he has some additional thoughts.
-Michael
> It's M132133
>
>
> ________________________________
> From: "ancestr2_at_host187.hostmonster.com"
> <ancestr2_at_host187.hostmonster.com>
> To: John Cooley Mailing List <undisclosed.recipients_at_johncooley.net>
> Sent: Monday, November 4, 2013 10:13 AM
> Subject: Re: Two basic genetic genealogy terms
>
>
> GEDmatch isn't working for me today. What's your kit number?
>
> -Michael
>
>> Michael, Have you gotten a chance to look at our match on GedMatch? If
>> so, any thoughts?
>>
>> Gloria
>
>
--
Second VP, the Cooley Family Association of America
Administrator, the Akins DNA Project
Administrator, the Ashenhurst DNA Project
Administrator, the Bishop DNA Project
Administrator, the Eldridge DNA Project
Administrator, the alt-McDowell DNA Project
Co-Administrator, the Cooley DNA Project
Co-Administrator, the McDougall DNA Project
Instructor "Genealogy and Family History," the Osher Lifelong Learning
Institute (OLLI)
B.A. Humboldt State University, History
Received on Mon Nov 04 2013 - 23:18:51 MST