Facing environmental predictability with different sources of epigenetic variation.

Area of Science:

• Evolutionary biology
• Epigenetics
• Genetics

Background:

• Epigenetic changes influence phenotypic variation, impacting adaptation.
• Environmentally induced epigenetic changes drive phenotypic plasticity.
• Stochastic epimutations contribute to diversifying bet-hedging strategies.

Purpose of the Study:

• To investigate the relative contributions of environmentally induced and stochastic epigenetic changes in fish from predictable vs. unpredictable environments.
• To test the hypothesis that the balance of these epigenetic sources reflects environmental uncertainty.
• To understand how these strategies contribute to an organism's capacity to respond to environmental conditions.

Main Methods:

• Assessed DNA methylation patterns in clonal fish populations.
• Compared epigenetic changes in fish from natural lake (predictable) and intermittent stream (unpredictable) environments.
• Validated findings using common garden experiments.

Main Results:

• Contrasting contributions of environmentally induced and stochastic epigenetic changes were observed based on environmental origin.
• Differences in epigenetic sources were confirmed in controlled common garden experiments.
• Both environmentally induced and stochastic epigenetic variations were found to act conjointly.

Conclusions:

• Distinct sources of epigenetic variation (plasticity vs. bet-hedging) are prevalent depending on environmental uncertainty.
• Plasticity and random epigenetic processes are complementary adaptive strategies.
• This study provides a framework for exploring organismal responses to environmental variability through epigenetics.