Genes, Brains, and Human Potential The Science and Ideology of Intelligence

68 PRETEND GENES

chapter 3), correlations between IQ and SNPs in GCTA studies are self-
fulfi lling (fi gure 2.4).
As an illustration, Charney draws attention to the Wellcome Trust’s
“ge ne tic map of Britain.” It shows strikingly diff er ent ge ne tic admixtures
among residents of diff er ent geographic regions of the United Kingdom.
Indeed, by analyzing rec ords, Dalton Conley and colleagues found a
correlation persisting between ge ne tic relatedness of pairs of “unrelated”
individuals and whether their ancestors lived in rural or urban envi-
ronments, back over as many as twenty- fi ve generations.^38 Likewise, an
association between ge ne tic resemblance and a crude mea sure of social
class (parental occupation and education) is what the Twins Early De-
velopment Study of UK twins found.^39 (Sadly but predictably, the cor-
relations tends to be interpreted as ge ne tic variation causing socioeco-
nomic status [SES]).
More recent analyses confi rm Charney’s suspicions. Youngdoe Kim
and colleagues tested the model under vari ous assumptions. Th ey con-
cluded that “heritability infl ation can be substantial, which indicates
heritability estimates should be interpreted with caution.”^40 Krishna
Kumar and colleagues have also warned that, with so many unlikely

social strata

SNP-SES correlation

that persists

across

generations

to produce

SNP-SES

correlations

generations

later

migrating population

FIGURE 2.4

How nonrandom ge ne tic distributions produce SNP- SES (and therefore SNP- IQ)

correlations over generations.

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