E.B. Ford was a close associate of Fisher and a pioneer of what he called ‘ecological genetics’, particularly the study of natural selection in natural populations. In 1945, Ford urged a search for associations between the ABO blood groups and disease in order to explain the selection he assumed was needed for the maintenance of the ABO polymorphism. The first such association, described in 1953 (ref. 4), was between ABO types and stomach cancer. A 1961 (ref. 5) summary of data on ABO and disease associations is shown in Table 1 (Table 5.4 in ref. 6). Several of the odds ratios (ORs) listed are on the high side of those now being found by WGAS for a variety of common chronic diseases, with similarly low probabilities. The genes determining ABO types were effectively the first candidate genes, but there is so far no convincing explanation for these associations. Indeed, they are almost forgotten, perhaps because of the much larger ORs later found for associations between HLA types and certain diseases.
