From a February 18 23andMe tweet:

Only about 2.4% of participants included in large-scale genetic studies have African ancestry.

Is this claim true?

  • 1
    Large scale genetic studies and the workings of 23andMe (and similar companies) are not the same. There's plenty of information around showing how the databases assembled by these companies are biased towards white caucasian populations (example: bbc.co.uk/programmes/w3cswh1d)
    – user22865
    Apr 10, 2019 at 7:34
  • 2
    Please add a link to the tweet.
    – Oddthinking
    Apr 10, 2019 at 10:07
  • 7
    I assume this means direct line to modern Africans, and not via Europe, Asia, Oceania, etc. Otherwise it should be 100%, surely.
    – Oddthinking
    Apr 10, 2019 at 10:09
  • 1
    A link would be facebook.com/23andMe/photos/… giving the source as genomebiology.biomedcentral.com/articles/10.1186/… Please edit this info in. Apr 10, 2019 at 10:30
  • So what if the claim is true? It merely demonstrates that the "studies" did not evenly sample the population of the US. Apr 10, 2019 at 17:19

1 Answer 1


Yes, this claim is true.

From "A standardized framework for representation of ancestry data in genomics studies, with application to the NHGRI-EBI GWAS Catalog",

African ancestries comprise 2.4 % of individuals but contribute 7 % of associations.

  • @Fizz If you have a better answer, I will accept it.
    – user48578
    Apr 10, 2019 at 5:05
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    @Fizz What are non-European populations?
    – user48578
    Apr 10, 2019 at 5:08
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    It depends on the criteria for including the study in the survey. And it's actually " For ongoing studies (e.g. 2011) in RePORT, GWAS accounted for only ~14%, ~3%, and < 1% for African American, Hispanic, or Jewish ancestry populations, respectively. " The number of studies on African-Americans is actually respectable, but the sample sizes are small. As for the other (US) minorities... not even that can be said. RePORT is based on US NIH grants, which explains their focus. Apr 10, 2019 at 5:25
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    But since US research tends to dominate in this area... "Subsequent analysis of published GWAS from PubMed using the same search terms produced 4,942 publications, of which African Americans accounted for ~3% with Hispanics and Jewish accounting for < 1%," Apr 10, 2019 at 5:27
  • 2
    Also, since quoted a tweet of 23andMe, commercial databases are also known for their extreme Caucasian bias: qz.com/765879/… Apr 10, 2019 at 5:29

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