Understanding evolutionary rescue and parallelism in response to environmental stress.

Area of Science:

• Evolutionary biology
• Population genetics
• Ecology

Background:

• Evolutionary rescue is crucial for species survival under environmental stress.
• The sequence of genetic mutations and demographic factors influences the success of evolutionary rescue.
• Understanding genotypic parallelism is key to predicting population persistence.

Purpose of the Study:

• To investigate genotypic parallelism in independent populations under environmental stress and varying demographic regimes.
• To determine how initial maladaptation and demographic factors affect the degree of parallel evolution.
• To analyze the transition between different demographic regimes influencing evolutionary rescue outcomes.

Main Methods:

• Developed analytical approximations for the probability of evolutionary rescue.
• Utilized simulation results to contrast with analytical findings.
• Examined evolutionary rescue under density regulation with two distinct demographic regimes.

Main Results:

• The initial level of maladaptation and the demographic regime significantly impact the extent of parallel evolution.
• A clear transition in parallelism was observed between the two demographic regimes.
• Parallelism decreased with increasing maladaptation in the first regime, while it increased in the rescue/extinction regime.

Conclusions:

• Demographic factors and initial maladaptation critically shape evolutionary rescue dynamics.
• The study highlights the interplay between population regulation, genetic adaptation, and extinction risk.
• Findings provide insights into population persistence and the predictability of evolutionary responses.