Genetic Constraints, Transcriptome Plasticity, and the Evolutionary Response to Climate Change

Area of Science:

• Ecology
• Evolutionary Biology
• Climate Change Biology

Background:

• Ectotherm species face challenges adapting to climate change due to limited dispersal.
• Climate change increases mean and variance in environmental temperatures, acting as selection pressures.
• Heritability and independent evolution of thermal performance traits are crucial for adaptation.

Purpose of the Study:

• Review literature on heritability of thermal performance traits in ectotherms.
• Examine gene expression responses to thermal stress.
• Identify genes involved in thermal adaptation and assess their evolutionary patterns.

Main Methods:

• Literature review on heritability of thermal performance traits.
• Analysis of gene expression data in response to thermal stress.
• Identification and analysis of candidate genes for thermal adaptation.

Main Results:

• Thermal tolerance limits are moderately heritable, suggesting rapid evolution potential.
• Performance at intermediate temperatures shows lower evolutionary potential.
• Genetic constraints limit adaptation to both increased mean temperature and variability simultaneously.
• Transcriptome plasticity in response to temperature shifts is common, with gene expression changes correlating with stress magnitude, not duration.
• Extreme weather events are more potent drivers of evolutionary change than gradual warming.

Conclusions:

• While tolerance limits can evolve, intermediate performance is a constraint.
• Phenotypic plasticity via gene expression is critical when genetic evolution is limited.
• Adaptation to climate change in ectotherms is complex, influenced by heritability, plasticity, and genetic correlations.
• Future climate change impacts on ectotherms will likely be driven by the frequency and intensity of extreme weather events.