of detectable trans-eQTLs (Table 2). The P values reported for the trans-eQTLs are lower than those for cis-eQTLs, owing to the higher statistical threshold required to achieve statistical significance. In general, a single SNP (eQTL peak) explained between 10 and 20% of the transcript's expression variance for cis- and trans-eQTLs, respectively (Table S1). However 6.8% of the cis acting SNPs explained more than 30% of the variance in the transcript and 15.3% of the trans acting SNPs explained more than 30% of a transcript's variance (Figure S1).
