Figure 1

Predicted allele frequencies in annual population of children 0–15 years of age plotted against calendar year, using the population genetic model for the incidence change. Transmission probability of the susceptibility allele 'A' from a heterozygous parent, τ, is 0.52 (---), 0.55 (-- --) and 0.6 (-- ··· --). Allele frequency of 'A' starts from = 0.15 in both figures. The transmission distortion effect is assumed to have been acting since the introduction of insulin in 1930s.