QQ-plot of p-values with GDF9 c.1111G>A SNP included. Comparison of p-value distributions when the GDF9 c.1111G>A SNP is added to the dataset (A), and when the GDF9 c.1111G>A SNP genotypes is included in the model as a covariate (B). The expected –log10(p) on the x-axis and the observed –log10(p) on the y-axis.
Våge et al. BMC Genetics 2013 14:1 doi:10.1186/1471-2156-14-1