View Full Version : Does 23andme underestimate admixtures?

06-16-2017, 11:49 PM
I was wondering because on most gedmatch calculators i get 5-8% Bedouin which is ancestry i know of however on 23andme i get 0.2% North African with a little European and South Asian making it a total of 1.0%. Is it 23andmes algorithm or sampling of certain populations that needs improvement?

On my ancestry timeline it says that my ggg grandfather at most was 100% North African or Arab which i already know is true. It also states that my GGGG grandfather was 100% South Asian. However, on my ancestry composition it dosent look like the ME/NA and South Asian ancestry is recent.

My ancestry timeline

My ancestry composition at 50% accuracy.

90% accuracy

My ancestry composition at 90% accuracy however gives me 95% SSA, 0.3% South Asian and 4.7% unassigned which could be the recent Middle Eastern and possibly South Asian ancestry i know of right? This is similar to my gedmatch, Myheritage and other ancestry tests ive done...

My results from myheritage dna

Gedmatch Dodecad Africa 9 is specifically aimed at africans with west eurasian ancestry.
Here are my results

06-17-2017, 12:39 AM
I think 23andme can definitely underestimate some admixtures. However, in your case it might be that your recent Arab ancestry is minor and most of your Eurasian admixture is more ancient (i.e. maybe Cushitic related). In that case your Eurasian might be eaten up by 23andme's "East African" component, which if I recall correctly is Horner-centric.

06-17-2017, 03:54 AM
Sometimes it does sort of wash away small segments of other stuff if they are surrounded by large segments of your main ancestry.