Trans-Acting Genotypes Associated with mRNA Expression Affect Metabolic and Thermal Tolerance Traits.

Area of Science:

• Genomics
• Physiology
• Evolutionary Biology

Background:

• Physiological trait variation is driven by genomic mechanisms, but their complexity and context-dependency make them hard to study.
• Understanding the genetic basis of physiological adaptation requires examining genotype-phenotype relationships and gene expression patterns.

Purpose of the Study:

• To investigate the genetic complexity underlying physiological trait variation.
• To determine if gene expression influencing physiological traits is primarily cis- or trans-acting.
• To link genomic polymorphisms to physiological traits via mRNA expression.

Main Methods:

• Low-coverage whole genome sequencing and tissue-specific mRNA expression (heart/brain) were employed.
• Expressed quantitative trait loci (eQTL) were identified for temperature-specific physiological traits.
• Analysis focused on mRNAs within co-expression modules explaining significant trait variation.

Main Results:

• Hundreds of significant eQTLs were identified for mRNAs influencing physiological traits.
• A high proportion of identified eQTLs were trans-acting (97.4% in heart, 96.7% in brain).
• Trans-acting eQTLs may have larger effect sizes, especially for central mRNAs in co-expression modules.

Conclusions:

• Trans-acting mRNA expression in the heart and brain is the predominant genomic mechanism driving physiological variation across environments.
• The study highlights the importance of trans-acting regulatory elements in shaping complex physiological traits.
• Focusing on co-expression modules may enhance the detection of trans-acting regulatory effects.