Heritability and tissue specificity of expression quantitative trait loci

Area of Science:

• Genetics
• Genomics
• Molecular Biology

Background:

• Gene expression variation is heritable and mapped via expression quantitative trait loci (eQTLs).
• Understanding eQTLs across different tissues is crucial for deciphering gene regulation.
• Rat recombinant inbred strains provide a model for studying genetic regulation of complex traits.

Purpose of the Study:

• To investigate the influence of heritability and allelic effects on the detection of cis- and trans-acting eQTLs.
• To analyze these factors within a tissue-specific context across fat, kidney, adrenal, and heart tissues.
• To assess the impact of genetic architecture on gene expression variation.

Main Methods:

• Integrated genome-wide expression profiling and linkage analysis in BXH/HXB rat strains.
• Identification and comparison of cis- and trans-acting eQTLs across multiple tissues.
• Heritability filtering and power calculations to evaluate eQTL detection sensitivity.

Main Results:

• Several hundred major eQTLs were identified in each tissue.
• Cis-acting eQTLs demonstrated higher heritability and detectability compared to trans-acting eQTLs.
• Heritability alone was not a definitive predictor of eQTL detection; filtering by heritability reduced trans-eQTL discovery, especially for small-effect eQTLs.

Conclusions:

• Heritability and allelic effects significantly influence eQTL detection in a tissue-specific manner.
• Trans-eQTLs generally have smaller effects, higher false discovery rates, and are more sensitive to tissue variability.
• Genetic architecture and experimental design, including tissue sampling, critically impact large-scale eQTL studies.