Heritable probe sets in lymphoblastoid cell lines. (A) The distribution of heritabilities (h²) for the normalized expression of 170,956 probe sets. The observed distribution (blue line) is shifted toward higher heritabilities, as compared to the expected distribution from permutation testing (red line). Of the probe sets, 22.4% fall to the right of the expected distribution, indicating that these are more heritable than random. (B) The locations of the 6536 most heritable (h² > 0.6 from A) probe sets within genes. Most probe sets occur within coding exons, although more occur in 3′-UTRs than expected by chance.