Adaptive and non-adaptive divergence in a common landscape.

Area of Science:

• Evolutionary biology
• Ecology
• Genomics

Background:

• Species in shared landscapes encounter similar environmental pressures.
• Organismal adaptive capacity can be species-specific.
• Understanding varied adaptive responses is key to explaining biodiversity patterns.

Purpose of the Study:

• To compare adaptive divergence in three-spined and nine-spined sticklebacks along a salinity gradient.
• To investigate species-specific neutral and adaptive genetic differentiation.
• To determine the influence of spatial and environmental factors on population divergence.

Main Methods:

• Comparative analysis of phenotypic differentiation.
• Assessment of neutral genetic differentiation.
• Genomic scans for signatures of adaptation.

Main Results:

• Three-spined sticklebacks exhibited stronger phenotypic, neutral genetic, and genomic adaptation signatures.
• Both species displayed significant phenotypic parallelism.
• Genomic regions under selection differed between species, indicating non-parallel adaptation.

Conclusions:

• Species exhibit distinct evolutionary strategies for persistence in common landscapes.
• Divergent genomic responses despite phenotypic parallelism provide insight into evolutionary versatility.
• This study illuminates mechanisms behind varying ecological success among species.