Combined linkage and association analysis using SOLAR v4.0.7 was performed to include identity by state information similar to the approach used by Almasy et al. (1999) where the variance in the SHAS score that cannot be accounted for by the covariate parameter based on the number of minor alleles was decomposed into the standard variance components. To see whether the linkage signal could be explained by the allele effects of a single SNP, each SNP marker was individually tested by including the number of minor alleles as a covariate. Polygenic covariate screening was used to calculate the significance level after the inclusion of any particular SNP and multipoint analysis was used to calculate the multipoint LOD score for the SHAS score.
