Adaptive Dynamics of Quantitative Traits in a Steadily Changing Environment

Area of Science:

• Evolutionary Biology
• Quantitative Genetics

Background:

• Understanding adaptation of quantitative traits to changing environments is a key challenge.
• The influence of environmental change speed and trait architecture on adaptive dynamics is not fully understood.

Purpose of the Study:

• Investigate the roles of environmental change speed and trait architecture in adaptive dynamics.
• Characterize quantitative traits using a novel dimensionless parameter, the effective selection strength.
• Develop a fitness-threshold-based critical speed to define population extinction.

Main Methods:

• Employed an adaptive walk model and individual-based polygenic simulations.
• Utilized a moving-optimum framework to simulate environmental change.
• Introduced and analyzed the effective selection strength parameter.

Main Results:

• Populations achieve a stationary state below a critical environmental change speed.
• The adaptive walk model approximates long-term polygenic adaptation.
• Derived a formula for phenotypic gap divergence near the critical speed.
• Revealed a power-law relationship between critical speed and effective selection strength.
• Demonstrated how genetic architecture is shaped by mutation-selection balance under environmental change.

Conclusions:

• The adaptive walk model offers a simplified approach for studying polygenic adaptation.
• The study provides insights into population extinction dynamics under environmental change.
• Results advance the understanding of evolutionary adaptation to dynamic environments.