GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2002-12 > 1040145670


From: "Joseph B. Lambert" <>
Subject: [DNA]
Date: Tue, 17 Dec 2002 11:24:15 -0600
In-Reply-To: <OE40EUzvaPeLjCdclVX0000225d@hotmail.com>


I have a question about the meaning of the percentages that are being
measured by DNAPrint. Each of us has eight great-grandparents, who each
contribute 12.5% of the descendant's DNA (barring cousin redundancy). If
seven of these are 100% European and one is 100% East Asian, the DNAPrint
result would be, approximately, 88% European and 12% East Asian. Now
imagine that this person had eight great-grandparents, each of whom
happened to have had this same mix of 88% European and 12% East Asian,
because all eight of them had a single East Asian great-grandparent along
with seven Europeans. Does this second individual also exhibit 88%
European and 12% East Asian? In other words, are the results additive? If
so, I could imagine that a person could get a result of 10-15% East Asian
just because there was an accumulation of East Asian blood, not because
this person had a single, full-blooded great-grandparent. Again, if so,
that means that the method is tracking more distant ancestry. I ask,
because I have seen the statement that the method is meaningless beyond
great-great-grandparents (who each contribute about 6% of our genome)
because of the 5% error. If not, I would imagine that significant (>5%)
contributions to non-European ancestry can show up by accumulation from
very distant, full-blooded ancestors.

Joseph B. Lambert

At 07:00 AM 12/17/2002, you wrote:
>Yesterday I received the results of this test. I had gambled on the hope
>that the test would show some trace of an allegedly full blooded Cherokee
>3rd great grandmother and a 4th great grandfather that was listed as
>"mulatto" on 1785 & 90 tax rolls. I gambled and lost - the test came back
>as 100% European.
>
>I just wanted to let everyone know that this test probably can not
>reliably "detect" anything much past a single 2nd great grandparent of a
>different group, due to the 5% "margin of error". If you do not have a
>good "paper trail" history of numerous ancestors before that level, of a
>different group, you should probably save your money, at this time.
>Possibly the accuracy will improve as the technology matures.
>
>Ernie Hurst
>
>
>==============================
>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

Joseph B. Lambert
Department of Chemistry
Northwestern University
2145 Sheridan Road
Evanston, IL 60208-3113
Telephone 847-491-5437
Fax 847-491-7713
E-mail
Website http://www.chem.nwu.edu/~lambert/



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