Slower environmental change hinders adaptation from standing genetic variation

Area of Science:

• Evolutionary biology
• Genetics
• Ecology

Background:

• Adaptation to environmental change is crucial for species survival.
• Previous studies on adaptation often used microbes, limiting applicability to natural species relying on standing genetic variation.
• The rate of environmental change can influence the effectiveness of adaptation, particularly concerning genetic drift and founder effects.

Purpose of the Study:

• To test how the rate of environmental change affects adaptation from standing genetic variation in a natural species.
• To investigate the impact of genetic drift and founder effects on adaptation under gradual environmental change.
• To explore the role of standing genetic variation in the fixation of beneficial genotypes.

Main Methods:

• Experimental evolution using self-fertilizing Caenorhabditis elegans populations.
• Implementation of sudden and gradual environmental change scenarios.
• Development of an inference model to analyze natural selection on extant genotypes.

Main Results:

• Sudden environmental change rapidly favored genotypes with high fitness in extreme environments.
• Gradual environmental change initially favored less fit genotypes, leading to the loss of optimal genotypes via drift and founder effects.
• Standing genetic variation can impede the fixation of the most beneficial genotypes due to interference.

Conclusions:

• Slower rates of environmental change can impede adaptation from standing genetic variation in natural species.
• Genetic drift and founder effects play a significant role in hindering adaptation under gradual environmental change.
• Standing variation for genotype-by-environment fitness interactions critically influences the pace and outcome of adaptation.