Fig 3. Local association plot in the PER1 locus.

The plot displays the significance, as indicated by the −log₁₀(p-value), of the associations between timing of the circadian acrophase, and genotype at polymorphisms flanking rs7221412. All significance values calculated with Fisher-Lee regression using an additive model, and adjusted for age, sex, and presence or absence of dementia. Blue squares indicate directly-genotyped polymorphisms; black square indicate polymorphisms whose genotypes were imputed (imputation quality score >0.90 for all imputed polymorphisms). Vertical black bars indicate the extent of the association peak. The black diamond indicates the index SNP rs7221412. The horizontal dotted line indicates the Bonferroni-corrected threshold for significance.