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Archiver > GENEALOGY-DNA > 2006-02 > 1139668533


From: Doug McDonald <>
Subject: Re: [DNA] "General" DNA test
Date: Sat, 11 Feb 2006 08:35:33 -0600
References: <BAY105-F24CFF942B9F88ACB43BDDDB9050@phx.gbl>
In-Reply-To: <BAY105-F24CFF942B9F88ACB43BDDDB9050@phx.gbl>


Beverly Kane wrote:
> Hello all
>
> I just finished watching the PBS program on African American Heritage
> which included DNA testing. I am familar with Y-DNA and mtDNA testing.
> My question what is the test that gives you the broader answers that
> were given on the program, ie, one person was, say, 70% African, 20%
> European, 5% East Asian, 5% Native American??
>
> I a wondering if such a test is available, what it is called, what labs
> perform it and any other input from you knowledgeable people.
>
> I am a female and I expect that I am 100% European ancestry. Would the
> results of such a test break the results down further than the category
> "European?"
>

If you look at the archives of this mailing list and search for
"DNAPrint" you will find vast amounts on this test. It is
very controversial.

Yes, it is available, see www.ancestrybydna.com. The company
is called DNA PRint Genomics, and it is called (here) "DNAPrint".
Its generic name would be "biogeographical".

This test tests the 22 autosomes, not the Y chromosome or the
mitochondria. The science behind it ... which it should be
emphasized at the very start, is extremely solid ... can best be
seen in a paper in Science, vol. 298, Dec. 20, 2002, p. 2381,
and in US Patent # 20040229231, which is the patent of this
proprietary test.

What is done is that somebody tests a large variety of people
around the world for autosomal "markers" that are to the best
degree possible found in one area of the world. There are some
markers such that people whose ancestors lived in one
general area of the world have one and only one of two possible
"bases" at a certain place on their chromosome, and people whose
ancestors have always lived anywhere else have the other value.
There are very few markers that do that perfectly, but that's
the goal. Barring perfection, you look for markers such that the
split is as close to 100% / 0% as possible, like 85/15. You find
say 175 of these (which is about how many DNAPrint uses) and test
somebody for them. You then use a computer program to predict,
as best as possible, the distribution around the world,
out of the set of people used to calibrate the test, where the testee's
ancestors came from.

This works.

HOWEVER, and this is where the controversy begins, becuase everybody
is in fact a mixture, and because not every marker has a 100/0 split
in truly "native" people, you only get an ESTIMATE of what
the testee's mix is. DNAPRrint, on their graphs, gives "confidence
intervals" which tell this. At least on my high definition TV set these
were clearly visible during the TV program when the data sheets
were waved around.

When somebody on that program was said to be "11%" Asian, that was
a rather loose statement. The program used an early version of the test that
used far fewer than 175 markers, and was more vague than the present one.
What the test really meant was that somebody had a 95% chance of being
somewhere between 0 and 25% Asian. That's a BIG difference in the
"feeling" somebody expecting pure African gets when hearing it,
from "11% Asian". They really COULD not have any Asian at all!

I, for instance, expected to be either 100% European or
about 97% European and 3% American Indian. In fact, the little
dots came back 97% European and 3% Asian. However, if I look at the
confidence contours, I could just as easily be 97% European and
3% American Indian, as 3% Asian, or indeed, pure European. So IN FACT
the test was exactly what I expected.

This was their main test, which tries to sort out African, European
(including Middle Eastern and India/Pakistani as European), American
Indian, and East Asian (Chinese). If you are Melanisian or an Australian
aborigine, this test will go totally bonkers.

They offer, for people who test almost all "European/Indian(i.e. India)/Middle Eastern"
on this test, another one which tries to sort out whether you are
north European, southern European (Mediterranean), Middle Eastern,
or South Asian (their term for India/Pakistan). Most people turn out
to be a mix on this, since they and almost everybody in Europe in fact are.

Doug McDonald

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