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Archiver > GENEALOGY-DNA > 2002-08 > 1030227706


From: "Pieter J. Cramwinckel" <>
Subject: Re: [DNA] How specific is 12 marker test
Date: Sun, 25 Aug 2002 00:21:46 +0200
References: <62.24b59274.2a9953f4@aol.com>


In all fairness, I think the question is an extremely valid one, and causes
a lot of concern for those who on a very incidental basis take the plunge
and go for a 12 markers test 'ad solo'
Ann Turner (list founder & administrator, bravo to her !) is very right in
pointing out that this question comes up quite frequently. I also noticed
that Ann is has a slight bias in favour of answering mtDNA questions in more
detail vs. Y str questions. And that is fine, we need experts on this list
of al sorts and on all topics.
Now note, that I am not one of them. I have gone the hard way, following
the topics and lurking on this list for some months and occasionally daring
to ask questions.
But let me give it a try, from what I have distilled from answers posted
here to questions such as yours, and from my own experience in running a
now 15 member surname test project (sorry; results are not posted until end
august / early Sep, and even then only about the first phase of 8
participants)
1. to jump into a 12 marker Y-test on your own is unlikely to bring results
in terms of relatedness, in spite of al the hype of ' finding your
ancestors' by the commercial firms offering this. 12 markers is simply not
refined enough, and if you have a frequent haplotype such as mine (152 hits
in the Ystr database Europe) the "risk' of having unrelated matches is even
greater. Quite frankly , I have 4 matches (12/12) in the FTDNA dB and I have
not bothered to contact any of those, as the surname is quite different. So
here I learned this lesson quite quickly, and I'm happy I did not go 'ad
solo'.
2.Only a 24 or 25 marker test reduces this 'non relatedness event
substantially, but again not entirely, when your haplotype is frequent. I
am waiting to see if any of those 4 12/12 matches upgrade to 25, and if they
did , but do not match, and with a different surname, it is still not worth
it.
2. a test such as yours only makes sense within a well established surname
DNA research project, within which test candidates with similar surnames
are compared to check weather they match (range is 10/12 to 12/12) with any
of the others in that surname project. Once they match, depending on the
solidity of the paper evidence, you go for a 25 marker test, so better the
time estimation to MCRA.
3. Hence, to go 'solo' in the hope of finding another matching distant
cousin is quite hopeless, for the following reasons and with following
exceptions:
a.- surname ancestor research ( with y chromosome tests of 12 or 25 markers
is only of value when:
- a surname, or similarity thereof is shared
- a certain hint in the paper trail that points already in that direction
- a degree of geographic proximity (hu hu : what does that mean anyway? 10
miles? 110 miles ?, what about emigration over 1000's miles?)
-. there is a likelihood, at least historically- when traditional
papertrail does not help-, that a relationship is possible. . This argument
is quite often a combination of the above with things such as religious
strife, wars, fleeing for economic reasons, similar profession / occupation,
similar traits etc., rumours in the family history, etc-
What are the exceptions?
- illegal child on the father's side: a child from the father born out of
wedlock. The new-born will share the same haplotype as the father, but the
surname might be different. Yet without prior knowledge, this is looking
for the needle in the haystack, a pure chance coincidence , unless family
lore has it recorded or has a rumour about it.
- Lost babies (yea, did this happen), or 'found' children, in churches,
community centres or social institutions.
Hope this helps, and possibly others will comment or add to this.
Pieter
----- Original Message -----
From: <>
To: <>
Sent: Saturday, August 24, 2002 11:26 PM
Subject: Re: [DNA] How specific is 12 marker test


> In a message dated 08/23/02 6:39:23 PM Pacific Daylight Time,
> writes:
>
>
> > I have the results of my 12 marker tests and noted that there are at
least
> > four people that match my profile 12 of 12. However these people all
have
> > different surnames from me and from each other and as far as I can tell
are
> > not related. If mutations have occurred at such a rate that people who
> > are not really related match my profile, then how valuable is the 12
marker
> > test? If I go to a 25 marker test will it eliminate some of these
people?
>
> This is a subject of endless debate on this mailing list! In fact, there
are
> people who have uncovered even more matches with different surnames than
you
> have. If you browse the archives for earlier in August, you can find the
most
> recent thread where this was reported. (Link to Browse off the URL below
my
> signature.) You probably have a relatively frequent haplotype.
>
> A 25 marker test would undoubtedly eliminate some of them, but that's
> probably not the best use of your money.
>
> Ann Turner
> GENEALOGY-DNA List Administrator
> http://lists.rootsweb.com/index/other/Miscellaneous/GENEALOGY-DNA.html
> DNA preservation kits: http://www.dnafiler.com
>
>
>
>
> ==============================
> To join Ancestry.com and access our 1.2 billion online genealogy records,
go to:
> http://www.ancestry.com/rd/redir.asp?targetid=571&sourceid=1237
>

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