Genetic and Environmental Similarities Drive Repeated Genomic Evolution in Island Lizards

Area of Science:

• Evolutionary Biology
• Genetics
• Ecology

Background:

• Evolutionary adaptation studies reveal how populations adapt to new environments.
• Understanding the predictability of evolution requires examining genetic and environmental influences on adaptation.
• Previous research has not fully explored how genetic and environmental factors shape evolutionary trajectories.

Purpose of the Study:

• To quantify repeated genetic adaptation in island-colonizing lizards.
• To investigate the roles of environmental-dependent and divergence-dependent processes in adaptation.
• To determine the extent and conditions for predictable local adaptation.

Main Methods:

• Studied repeated genetic adaptation in lizards across multiple islands with similar environmental gradients.
• Quantified genetic reuse and evolutionary trajectory similarity.
• Analyzed 149 genes showing repeated adaptation, focusing on thermal physiology and developmental processes.

Main Results:

• Identified 149 genes involved in repeated adaptation, particularly in thermal physiology and development.
• Observed stronger genetic reuse at the functional level than at the mutation level, exceeding random expectations.
• Found that adaptive trajectories were more similar in islands with low genetic differentiation and similar environments.

Conclusions:

• Different genetic combinations can lead to similar functional outcomes in adaptation.
• The predictability of local adaptation is influenced by both genetic and environmental factors.
• The interplay between genetic and environmental factors shapes the repeatability of evolutionary adaptation.