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From:
Subject: Re: [DNA] Is anyone aware of an existing mtDNA Project to trace matrilineal
Date: Thu, 2 Jan 2003 12:15:33 EST

In a message dated 12/31/02 9:01:36 AM Pacific Standard Time,
writes:

> If, operating on a guess, one found a likely mother ("A") of this female
> ancestor, and then traced the matrilineal descent of another of this
> mother's daughters (in other words, a sister, "C", of the female
> ancestor mentioned above) to a living person ("5"), and the mtDNA
> of "5" exactly matched the results for "1", "2", "3", and "4", what
> does this tell about the relationship of these five living descendents
> of "A"? Of the likely relationship of "B" to "C"? What if "A" came
> from a small village in an Alpine valley?


If the mtDNA of all five matched exactly (or possibly have one difference),
that would support but not prove your hypothesis that A is the mother. The
mother could be A's sister or a matrilineally related cousin of some degree.
On the other hand, a mismatch would definitely rule out your hypothesis.

It would not be necessary to test 1 & 2 & 3 & 4 -- anyone of them would be
sufficient to compare with 5, unless you want to confirm your paper trail for
their common ancestor.

There are two additional factors which you can consider when you are weighing
the evidence.

One is the frequency or rarity of the haplotype (complete set of mutations)
in Europe generally. You can estimate that from online databases such as the
Mitochondrial DNA Concordance. If you happen to have a common haplotype, that
makes it more likely that a match could be a random coincidence. However,
paradoxically, most haplotypes are rare, so you can cross that bridge when
you come to it.

Second is the frequency of the haplotype in that small Alpine village. That
would be harder to estimate, but one study found a lot of haplotype diversity
in one German village: there were 460 different haplotypes out of the sample
of 1200, with 305 of those occurring only one time. The single most common
type was the Cambridge Reference Sequence, about 10% of the sample. (Pfeiffer
et al, Int J Legal Med (2001) 114:169-172).

Unless the small Alpine village was extremely isolated, it would probably
have a similar amount of haplotype diversity. So I'd say that if you do find
a match (and the haplotype is not too common), it may not prove that A
specifically is the mother, but you'd be looking at the right family.

Ann Turner
GENEALOGY-DNA List Administrator
>http://lists.rootsweb.com/index/other/Miscellaneous/GENEALOGY-DNA.html
DNA preservation kits: >http://www.dnafiler.com

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