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Archiver > GENEALOGY-DNA > 2011-11 > 1321124759


From: "Lancaster-Boon" <>
Subject: [DNA] Correct TMRCA analysis (ancient V13)
Date: Sat, 12 Nov 2011 20:05:59 +0100


Dear Anatole


For reference, here is my original post you are reply to:
http://archiver.rootsweb.ancestry.com/th/read/GENEALOGY-DNA/2011-11/13211082
93

Going through your post:

"an unspecified number of 16 marker haplotypes"
The E-M35 project has a quite large dataset. I do not have a handy number,
but it hardly matters in this discussion. The modal has been stable over
many years of collecting new members. I think however you've worked with us
before on an earlier version of the same dataset. Of course these are
genealogists, and they have mostly tested more than the 16 markers tested in
the recently announced Avellaner find. I only mention 16 markers because
that is what was tested in the ancient sample.

"no base (identical to each other) haplotypes"
I am not so clear why you say this, but that might be because I am not so
clear why and how you are using the term "base haplotype". The ancient V13
found in Spain was of course a data set of only one. If we look at the 16
markers tested in that paper, and then go to our modern project dataset I
would extremely surprised if we did not have many haplotypes which are
identical.

""a large number" of haplotypes have 3 mutations from the base haplotype"
Well, a large number of samples in our genealogical data set have 3
mutations from the one single ANCIENT SAMPLE. The number of people who are 4
mutations away is larger.

"something has "at least 5" mutations from the base haplotype"
Again your use of non-standard terminology seems to confuse the issue. My
words were that the genetic distance of the one single Ancient sample, from
Avellaner, "from our modern V13 modal is at least 5 over 16 markers". The
reasons for the words "at least" is because I did not have a handy modal
value for DYS635, because FT DNA only recently started testing for it in a
standard panel.

"I have sensed that 3 mutations is probably an approximately average number
of mutations from the base haplotype."
I am really not sure how you could send that, but then again I am not sure
what you mean by the base haplotype. One thing you could draw from my post
is that the average number of mutational steps between the one single
ancient sample and our modern E-V13 genealogists is probably at least 5. If
it was a modern sample, within our database, I would think this one sample
is not strikingly unusually different from the modal.

"Regarding the lack of the base haplotypes in the dataset"
Once again my apologies for not being used to your terminology, but I am
sensing that by this you are saying that E-V13 has no obvious clusters with
their own recent common ancestors that they do no share with the rest of
E-V13. This is not totally correct. There are a few but they all look quite
young. This might be consistent with what you are saying though.

Best Regards
Andrew

---
My original post:
If I am not mistaken we have no perfect matches for this haplotype in the
project. BUT we have 3 people with a GD of 2, and a large number with a GD
of 3. Basically you can say that with a GD of 3 you start getting close
already to the dense core of E-V13 clustering.

Anatole:
If I properly understood your rather cryptic (to me) note, you said that
among an unspecified number of 16 marker haplotypes in a E-V13 dataset there
are no base (identical to each other) haplotypes, three haplotypes on the
list have 2 mutations from the base haplotype, "a large number" of
haplotypes have 3 mutations from the base haplotype, and something has "at
least 5" mutations from the base haplotype.

I have sensed that 3 mutations is probably an approximately average number
of mutations from the base haplotype.

If your 16 marker haplotypes are the same as 17 marker ones (minus
DYS425=0), then the mutation rate constant for them equals to 0.002
mutations per marker per conditional generation of 25 years, that is 0.034
per 17 marker haplotype. If so, the (approximate) TMRCA for your dataset is
3/0.034 = 88 --> 97 generations, that is ~ 2425 years to a common ancestor
for your series of haplotypes. It is just about what follows from the
considered Cruciani (2007) and Battaglia (2008) datasets.

Regarding the lack of the base haplotypes in the dataset, it is of no
surprise. In order to have even 3 base haplotype in the series (derived from
one common ancestor) you should have at least 60 of 17/16 marker haplotypes
on the list. Check: [ln (60/3)]/0.034 = 88 generations --> 97, that is the
above 2425 years to a common ancestor. Of course, those three haplotypes in
reality will easily be 3+/-1.


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