Comments on: New Feature: Ancestry Painting http://spittoon.23andme.com/2008/03/25/new-feature-ancestry-painting/ A receptacle for genetic knowledge. Sat, 13 Feb 2010 03:51:43 +0000 http://wordpress.org/?v=2.9 hourly 1 By: MikeM http://spittoon.23andme.com/2008/03/25/new-feature-ancestry-painting/comment-page-1/#comment-149 MikeM Wed, 26 Mar 2008 20:22:35 +0000 http://spittoon.23andme.com/2008/03/25/new-feature-ancestry-painting/#comment-149 Thanks for the compliment, and for a great question. You are interpreting the picture correctly; the display for the African American individual is showing a handful of short stretches of Asian ancestry from both parents. These stretches arise most likely from statistical "noise", which is to say that they probably do not represent true Asian ancestry. A white paper with full details of our procedure is shortly to appear on the site for the motivated; this paper will include a discussion of artifacts of this kind and our plans to reduce their occurrence. With that said, our extensive testing indicates that Ancestry Painting gives high-quality results, and we hope that people will enjoy this new look into their personal genetic history. Thanks for the compliment, and for a great question. You are interpreting the picture correctly; the display for the African American individual is showing a handful of short stretches of Asian ancestry from both parents. These stretches arise most likely from statistical “noise”, which is to say that they probably do not represent true Asian ancestry. A white paper with full details of our procedure is shortly to appear on the site for the motivated; this paper will include a discussion of artifacts of this kind and our plans to reduce their occurrence. With that said, our extensive testing indicates that Ancestry Painting gives high-quality results, and we hope that people will enjoy this new look into their personal genetic history.

]]> By: gcoop http://spittoon.23andme.com/2008/03/25/new-feature-ancestry-painting/comment-page-1/#comment-148 gcoop Wed, 26 Mar 2008 18:02:07 +0000 http://spittoon.23andme.com/2008/03/25/new-feature-ancestry-painting/#comment-148 A nice feature. I wondered if it is just a distortion from looking at these images at small scale, but it appears that the African American individual is often homozygous for Asian ancestry at various points along the chromosome where they have some Asian ancestry. Am I interpreting the picture correctly? If so, is this result strange? If I am looking at a chromosome (e.g. chromosome 4) where one copy seems to be inherited from a European parent and the other copy seems to be inherited from an African parent, should I expect to see a number of patches where both parents have contributed Asian ancestry at exactly the same region? Graham Coop A nice feature.
I wondered if it is just a distortion from looking at these images at small scale, but it appears that the African American individual is often homozygous for Asian ancestry at various points along the chromosome where they have some Asian ancestry. Am I interpreting the picture correctly?

If so, is this result strange? If I am looking at a chromosome (e.g. chromosome 4) where one copy seems to be inherited from a European parent and the other copy seems to be inherited from an African parent, should I expect to see a number of patches where both parents have contributed Asian ancestry at exactly the same region?

Graham Coop

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