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From:
Subject: Re: [DNA] OT How many races are there?
Date: Wed, 17 Mar 2010 18:52:12 EDT


That's due to the limited number of ancestry informative markers available
at that time. DNAPrint originally planned to show five groups (Pacific
Islanders would have been the next group to pop out), but the results were too
fuzzy.

Some other messages have mentioned splitting results into K groups. Here's
a classic paper that illustrates what happens for K = 2 to 6 (see Figure 1).
The markers for this study are 377 microsatellites. The populations are
the same Human Genome Diversity Project panels that get used over and over
again. 23andMe uses these same groups to position you on the Advanced Global
Similarity diagram, and deCODEme has a similar diagram that can be rotated to
show more dimensions.


http://www.stanford.edu/~joelv/teaching/167/rosenberg%20etal%2002%20-%20genetic%20structure%20of%20human%20populations.pdf

Ann Turner

In a message dated 3/17/2010 12:45:54 PM Pacific Daylight Time,
writes:

> They could have picked 8 or 12 groups, if they wanted to, but the test
> results for the major "racial" component of each person's ancestry would not
> be consistently correct, otherwise they would have used a different number
> of groups than they did--which was four.


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