GENEALOGY-DNA-L Archives

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Subject: [DNA] News item: African ancestry (and musings on full sequencedata)
Date: Wed, 7 Feb 2007 12:56:59 EST

This column is about African ancestry (generic term) with background
information on African Ancestry (the company).

http://www.diverseeducation.com/artman/publish/article_6971.shtml

One of the points of contention seems center around the accuracy of African
Ancestry's claims. Those claims vary in strength -- from ten-word headlines on
the splash page to grab your attention:

"One simple test can identify your family's country of origin."

http://africanancestry.com

to a more detailed (and accurate) explanation in finer print if you click on
the headline:

"If the ancestry is African, the MatriClanTM Test can identify the
present-day African region with which you share genetic maternal ancestry."

African Ancestry does have a very large database, gathered at great expense
I'm sure, so there's no competition in that regard. However, Bert Ely and Bruce
Jackson, quoted in the article, have written an article about the impact of
common and rare haplotypes:

http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1618861&blobtype=pdf

Since I have full sequence mtDNA results on the brain lately, I got to
thinking about whether a higher resolution test would end the controversy (never
mind the cost -- this is a thought experiment). If my hypothesis about my close
match on a full sequence is correct, a mutation appeared in my line sometime in
the past 400 years. That's a pretty high resolution.

Yet I have seen sequences which must have remained unchanged for thousands of
years. For instance, if you look at the master phylogenetic tree at MitoMap
(integrating sequence data from dozens of citations), you'll see that data from
haplogroup H occupies almost the whole bottom line, with hundreds of
sequences harboring varying numbers of mutations.

http://www.mitomap.org/mitomap-phylogeny.pdf

Zooming in on the lower right-hand edge, you can see that a small percentage
of samples still have absolutely no mutations since the clan mother -- who
knows what varied migration routes those descendants might followed? Yet a sample
with 10 mutations is shown close by -- surely that sequence would have a more
limited geographic distribution. If only random mutations weren't *quite* so
random!

Bottom line -- full sequence testing could certainly improve matters, but it
wouldn't necessarily get to the 100% level of identifying a geographical
origin in historical times.

Ann Turner

This thread:

• [DNA] News item: African ancestry (and musings on full sequencedata) by

  • Re: [DNA] News item: African ancestry (and musings on fullsequence data) by (John Chandler)