Comparison of eQTL profiles. An example eQTL profile for microarray probe set 1426838_at (Pold3) from the hippocampus data set, using RFSF (A) as the importance measure. Loci near genes participating in the same pathway (DNA replication) as the target gene (Pold3 - a DNA polymerase) are marked with circles. The 99th percentile of the values in this profile is marked with a dashed line. (B) The same target probe set, using HK as the eQTL mapping method. The traditional mapping methods based on the LOD score tend to have very broad, blunt peaks, sometimes spanning most of a chromosome. Random Forests, on the other hand, produces very sharp, narrow peaks.