Educability-and-Group-Differences-1973-by-Arthur-Robert-Jensen

Intelligence of Racial Hybrids 221
average differences in Caucasian admixture between Negroes in
the South and those in the North and West. The frequency of
genes of African origin in the white population, on the other hand,
is estimated at less than 1 percent (Reed, 1969b).
The method of estimation of degree of racial admixture is
based on analysis of blood groups. There are a number of blood
proteins, or antigens, which have markedly different frequencies
in African and European populations. When the average frequencies
of these blood groups are known for the ancestral populations (in
this case West Africans and West Europeans) which gave rise to
the hybrid population, it is possible to determine the relative
degree of admixture of the two ancestral populations in the hybrid
group by analysis of the frequencies of the blood groups in the
hybrid sample. The accuracy of the estimate depends upon several
factors: (a) the size and representativeness of the sample, (b) the
number of blood groups used, (c) the exactness of the estimates
of the frequencies of the blood groups in the ancestral populations,
and (