Figure 3. Fertility varies with genotype at two candidate sites under selection.

Hutterite families in which wives have more copies of the derived ZP2 36 Gly allele have fewer children (A), and families in which husbands have more copies of the derived C4BPA 300 Ile allele have higher birth rates (B). Horizontal bars show means for each genotype class. Plotted values are residuals from linear model analyses (GEMMA) that account for three other covariates (wife’s birth year, age at marriage, time from marriage to last birth); estimates of the statistical significance of those residual relationships also account for pedigree relatedness among families.