DNA Ancestry Tests: Simultaneously Powerful and Limited

Posted in Articles, Health/Medicine/Genetics, Media Archive on 2013-04-10 14:44Z by Steven

DNA Ancestry Tests: Simultaneously Powerful and Limited

KQED: Public Media for Northern California

Dr. Barry Starr, Geneticist-in-Residence
Tech Museum of Innovation, San Jose, California

Using a common DNA ancestry test, President Obama would be 100% Caucasian.

Sometimes genetic tests aren’t as useful as you think they will be. For example, if President Obama were to take a common ancestry DNA test, it would almost certainly come back as 100% Caucasian. Useful, huh?

This sort of test, a mitochondrial DNA (mtDNA) test, can look into the deep past but it can only see mom’s side of the family. And it isn’t even really that powerful. It not only ignores dad’s side of the family, but in reality it can only see a sliver of mom’s as well…

…The other kind of test, the Y chromosome test, can go as far back along the paternal line as the mtDNA test can along the maternal line but it suffers from the same problems. In fact, a surprising number (35%?) of African-American men actually have Caucasian Y chromosomes (well, given plantation life, maybe not so surprising). None of these men will learn anything about their African heritage with this test.

So the bottom line is don’t put too much faith into DNA testing alone. It is kind of fun to trace back your history this way but you are really only following one strand of your ancestral web back in time. The rest of the web is invisible to DNA testing…

Read the entire article here.

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