Here are a few example SNPs I have computed ancestral alleles for:rs115724926 ancestral allele: C a1, a2: T C
rs76558199 ancestral allele: C a1, a2: T C
rs115097218 ancestral allele: A a1, a2: C A
rs73912893 ancestral allele: T a1, a2: C T
rs148989228 ancestral allele: C a1, a2: T C
rs188353846 ancestral allele: C a1, a2: A C
rs183990933 ancestral allele: A a1, a2: G A
rs150703965 ancestral allele: C a1, a2: T C
rs12754304 ancestral allele: G a1, a2: A G
Could you check a few of them to see that my calculations are correct? I'm getting curious results like:ACB 0.915314274671
ASW 0.91517916277
BEB 0.917049238231
CDX 0.916604144085
CEU 0.916312368517
CHB 0.916396070154
CHS 0.916384565614
CLM 0.916188882557
ESN 0.915038231054
FIN 0.916286699506
GBR 0.916317467703
GIH 0.917061446611
GWD 0.915371030784
IBS 0.916431791717
ITU 0.917123471431
JPT 0.916327029174
KHV 0.916603507552
LWK 0.914944244915
MSL 0.915354857881
MXL 0.916200977742
PEL 0.916411334999
PJL 0.91699048296
PUR 0.916128942459
STU 0.917130458765
TSI 0.91637858723
YRI 0.914866869338
I thought it was known that AFR were more ancestral?
I checked them using 1KG browser and yes they are right. Honestly I thought the frequency of ancestral alleles would be lower but this is because the other studies I read used completely different polymorphisms, i guess they used polymorphisms with a much higher mutation rate. They had found higher frequencies of derived alleles among non-Africans and explained this in terms of genetic drift. However, they are wrong because genetic drift predicts that ancestral alleles are higher among non-Africans. In fact, the lower the frequency of a mutation, the higher the probability that it will disappear from a population if the population is smaller (non-African) and subject to drift. So yes this is what I had expected to find.
Well if these frequencies are real, controlling for them is not gonna weaken our results. To the contrary..