Extended Data Fig. 2: Comparison of the heritability for 184 matched plasma and urine metabolites with at least one mQTL.
The positive correlation between the estimated heritabilities for a given metabolite’s plasma and urine levels is consistent with the metabolites’ filtration from plasma to urine, without substantial additional genetic influences on their tubular handling. The blue line is the linear regression line and the gray shaded area represents the 95%-confidence interval. Differences in estimated heritability for plasma and urine (instances with >25% are labeled with the associated metabolite and most likely gene; error bars represent h2 variance) can contain interesting biological information: for example, three metabolites with larger estimated heritabilities in urine than in plasma are N-acetylated amino acids, all of which have an mQTL at NAT8. NAT8 is highly and selectively expressed in the kidney, where the encoded enzyme N-acetylates molecules to make them water soluble for subsequent excretion.
