Borrowed alleles and convergence in serpentine adaptation

Area of Science:

• Evolutionary biology
• Genomics
• Plant science

Background:

• Serpentine barrens present extreme challenges for plant survival, including drought, nutrient deficiency, and metal toxicity.
• Despite these harsh conditions, plant populations have evolved adaptations to colonize these environments.

Purpose of the Study:

• To investigate the evolutionary genomic basis of adaptation in autotetraploid Arabidopsis arenosa to serpentine habitats.
• To identify genetic loci and evolutionary strategies involved in surviving multichallenge serpentine environments.

Main Methods:

• Population-based evolutionary genomic analysis.
• Elemental profiling of serpentine-adapted plants.
• Genome scanning through resequencing of Arabidopsis arenosa individuals.
• Comparison with independent serpentine colonization studies in Arabidopsis lyrata.

Main Results:

• Serpentine-adapted plants exhibit significantly altered elemental accumulation.
• Evidence for localized selective sweeps indicates a polygenic basis for adaptation.
• High overlap in differentiation loci with Arabidopsis lyrata suggests convergent evolution.
• Footprints of selection detected despite substantial gene flow from non-serpentine populations and A. lyrata.

Conclusions:

• Adaptation to serpentine barrens is likely driven by a limited set of evolutionary strategies.
• Convergent evolution plays a role, with shared genetic loci identified across species.
• Introgression from related species, like Arabidopsis lyrata, may facilitate adaptation to challenging environments.