Strong evidence of <i>cis</i>-mediation is detected only when the lead <i>trans</i>-eSNP and the lead <i>cis</i>-eSNP for the mediating transcript are in strong LD.

<p>The proportion of a <i>trans</i>-eQTL mediated by a <i>cis</i>-transcript (i.e., the “mediation proportion) is plotted against the negative log₁₀ of the Sobel P value for mediation for “FDR-significant” <i>trans</i>-eQTLs (panel A) and for “suggestive” <i>trans</i>-eQTLs (panel B). The plot is truncated at a Sobel P value of 10⁻¹⁶. Two outliers with a “mediation proportion”>2 have been excluded from panel A.