Comparing Admixtures of Siblings and of Parent and Child(ren)

Recently Judy Russell demonstrated for her blog followers why ethnicity estimates provided by testing companies could not be trusted in her post "Those Percentages, Revisited." I knew problems in my family's admixture results were present in the results, but until Judy posted the table, I never thought of creating one for my own family.

Using the results from the same company Judy used, I created a table.

Country	Me	Brother1	Brother2	Dad	Niece
British Isles	69%	67%		27%	84%
Scandinavia	19%	6%
Southern Europe	3%	7%
Western and Central Europe		18%	100%	73%	15%
Asia Minor	9%	2%
West Africa					1%

Let me make a quick note. The niece is the daughter of "Brother2." Is it not interesting that he is 100% of Western and Central European ancestry, but that she only has 15% rather than the expected 50%? She has rather strong British Isles ancestry.

I seem to have missed out on the Western and Central European ancestry, but I have a high percentage of "Asia Minor." I have a rather high percentage of Scandinavian ancestry according to this estimate, but only one brother shares any of that with me, and it apparently came from my mother's side of the family.

I decided to compare the admixtures at another site, but unfortunately I cannot include Brother2 in these admixture results as he only tested at the one company.

Country	Me	Brother1	Dad	Niece
Great Britain	70%	48%	52%	85%
Ireland	11%	27%	31%	9%
Italy/Greece	8%	10%	6%
Europe East	4%		< 1%
European Jewish	4%
Finland/Northwest Russia	1%	2%	1%	4%
Scandinavia	< 1%	1%	5%	<1%
Europe West	< 1%	9%
Iberian Peninsula			2%
Caucasus	2%	2%	2%
Benin/Togo		< 1%
African Southeastern Bantu			1%
Mali				< 1%
Africa North				< 1%

Overall these results seem to be a little less erratic than the earlier ones, but differences still exist. I find the differences between testing companies fascinating. I'm the only one who has tested with 23 and Me so I cannot determine how different admixtures are between siblings and/or parents.

Admixture remains the least reliable part of the DNA test. It's fun to see, but one should not rely too much on the results returned.