Heritability and tissue specificity of expression quantitative trait loci

Enrico Petretto*, Jonathan Mangion, Nicholas J. Dickens, Stuart A. Cook, Kumaran Kuppusamy Mande, Han Lu, Judith Fischer, Henrike Maatz, Vladimir Kren, Michal Pravenec, Norbert Hubner, Timothy J. Aitman

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    157 Scopus citations

    Abstract

    Variation in gene expression is heritable and has been mapped to the genome in humans and model organisms as expression quantitative trait loci (eQTLs). We applied integrated genome-wide expression profiling and linkage analysis to the regulation of gene expression in fat, kidney, adrenal, and heart tissues using the BXH/HXB panel of rat recombinant inbred strains. Here, we report the influence of heritability and allelic effect of the quantitative trait locus on detection of cis- and trans-acting eQTLs and discuss how these factors operate in a tissue-specific context. We identified several hundred major eQTLs in each tissue and found that cis-acting eQTLs are highly heritable and easier to detect than trans-eQTLs. The proportion of heritable expression traits was similar in all tissues; however, heritability alone was not a reliable predictor of whether an eQTL will be detected. We empirically show how the use of heritability as a filter reduces the ability to discover trans-eQTLs, particularly for eQTLs with small effects. Only 3% of cis- and trans-eQTLs exhibited large allelic effects, explaining more than 40% of the phenotypic variance, suggestive of a highly polygenic control of gene expression. Power calculations indicated that, across tissues, minor differences in genetic effects are expected to have a significant impact on detection of trans-eQTLs. Trans-eQTLs generally show smaller effects than cis-eQTLs and have a higher false discovery rate, particularly in more heterogeneous tissues, suggesting that small biological variability, likely relating to tissue composition, may influence detection of trans-eQTLs in this system. We delineate the effects of genetic architecture on variation in gene expression and show the sensitivity of this experimental design to tissue sampling variability in large-scale eQTL studies.

    Original languageEnglish (US)
    Pages (from-to)1625-1633
    Number of pages9
    JournalPLoS Genetics
    Volume2
    Issue number10
    DOIs
    StatePublished - Oct 1 2006

    ASJC Scopus subject areas

    • Ecology, Evolution, Behavior and Systematics
    • Molecular Biology
    • Genetics
    • Genetics(clinical)
    • Cancer Research

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