Linkage and association analysis on chromosome 4. Graphical representation of analyzing the same markers for linkage and association analysis. The continuous line is a plot of the MERLIN LOD score p-value [plotted as -log(p-value)] by genetic location (in cM). The red symbols represent the p-values [plotted as -log(p-value)] of the five SNPs that were found to be most powerful using the PBAT screening strategy. The black dots represent the PBAT p-values for all other SNPs tested. The dotted horizontal reference line corresponds to the 5% significance level for the five most powerful PBAT SNPs, Bonferroni-adjusted for five tests (or the 0.01 significance level unadjusted).