Gene-by-environment Interactions and Adaptive Body Size Variation in Mice From the Americas

Area of Science:

• Evolutionary biology
• Genetics
• Ecology

Background:

• Genotype-phenotype relationships are influenced by environmental factors.
• Gene-by-environment (GxE) interactions contribute to phenotypic and fitness variation.
• House mice (Mus musculus) show rapid adaptation to new climates in the Americas.

Purpose of the Study:

• Investigate the role of environment and GxE interactions in adaptive phenotypic variation.
• Identify genetic mechanisms underlying adaptation in house mice.
• Understand how diet and climate shape gene expression and regulation.

Main Methods:

• Utilized locally adapted inbred mouse strains from North and South America.
• Evaluated phenotypic and transcriptional responses to a high-fat diet.
• Employed crosses between strains from contrasting climates to study gene expression divergence.

Main Results:

• Sex, strain, diet, and strain-diet interactions significantly affected body size variation.
• Transcriptional responses to diet were largely strain-specific, indicating pervasive GxE effects on gene expression.
• Gene regulatory divergence was condition-specific, with evidence for lineage-specific selection on cis-regulatory variation.

Conclusions:

• Environmental variation and GxE interactions are crucial drivers of adaptive phenotypic variation.
• GxE interactions play a significant role in shaping gene expression and regulatory divergence.
• Identified candidate genes for environmental adaptation with diet-specific effects.