Cell-to-cell stochastic variation in gene expression is a complex genetic trait

Area of Science:

• Genetics
• Systems Biology
• Molecular Biology

Background:

• Complex traits often exhibit incomplete penetrance, where genotype does not guarantee phenotype.
• This variability is typically attributed to gene-gene or gene-environment interactions.
• Rare cellular events contribute to traits like cancer, suggesting a role for stochasticity.

Purpose of the Study:

• To investigate how natural genetic variation affects gene expression noise.
• To explore the genetic basis of stochastic cell-to-cell variations.
• To understand the link between genetic background and molecular noise levels.

Main Methods:

• Utilized yeast (Saccharomyces cerevisiae) as a model system.
• Analyzed gene expression noise across divergent genetic backgrounds.
• Employed Quantitative Trait Loci (QTL) mapping to identify genetic loci influencing noise.

Main Results:

• Observed reproducible differences in gene expression noise between yeast strains.
• Demonstrated that noise is highly heritable and under complex genetic control.
• Mapped three QTLs for noise, with one linked to impaired transcriptional elongation.

Conclusions:

• Natural genetic variation influences the level of stochasticity in gene expression.
• The genetic architecture of noise buffering impacts robustness and the probabilistic nature of complex traits.
• Genotypic background can modulate molecular noise, providing a basis for understanding trait variability.