Plastic responses to past environments shape adaptation to novel selection pressures

Area of Science:

• Evolutionary biology
• Ecology
• Genomics

Background:

• Phenotypic plasticity is crucial for adaptation to new environments.
• Evidence suggests initial plastic responses can promote subsequent adaptation.
• The role of plasticity to ancestral cues (past-cue plasticity) in adapting to novel cues remains unclear.

Purpose of the Study:

• To investigate the role of past-cue plasticity in adaptation to novel environmental cues.
• To determine if ancestral plasticity to past cues can facilitate adaptation to new challenges.

Main Methods:

• Examined gene expression plasticity in two mine-waste-adapted Silene uniflora populations and their coastal relatives.
• Exposed plants to ancestral (salt) and novel (zinc) environmental cues.
• Analyzed gene expression changes to identify patterns of plasticity transfer and fixation.

Main Results:

• Plasticity to salt diminished in mine-waste-adapted populations.
• Ancestral salt plasticity substantially impacted subsequent zinc adaptation.
• Salt plasticity transferred to zinc response in a third of evolved genes.
• A quarter of fixed expression differences mirrored ancestral salt responses.

Conclusions:

• Ancestral past-cue plasticity significantly contributes to rapid, parallel adaptation to novel habitats.
• Plastic responses to ancestral cues can be preadaptive or transferred to novel cue responses.
• Past-cue plasticity is a key factor in evolutionary adaptation to changing environments.