Wednesday, June 21, 2006

So Much for the Trip to Mongolia

The New York Times today shared something that was already known in genetic genealogy circles. Many newspapers have reported recently on a Florida professor's link to Genghis Khan -- discovered via DNA testing.

But it turns out not to be the case. See Falling From Genghis's Family Tree for details about why the poor fellow will no longer be traveling to Mongolia.

The problem is that the initial test used was low resolution (only 9 markers). And the problem with low resolution tests is that they can lead to false positives -- as in this case.

In other words, two fellows who get DNA tested and match 9-for-9 markers might only match, say, 28 for 37 markers if tested at a higher resolution (incidentally, tests are now available for up to 66 markers). In short, they don't really match at all and therefore do not share a common ancestor.

This is exactly why I'm always discouraging low-res testing when I speak. On a village project of mine, I've found about a 20% rate of false positives.
So please, if you decide to enter the world of genetealogy, invest in a test with at least 20-some-odd markers -- preferably more. Sure, the low res ones are cheaper, but as this amply demonstrates, they can be extremely misleading.


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