Cryptic genetic variation promotes rapid evolutionary adaptation in an RNA enzyme

Area of Science:

• Evolutionary biology
• Molecular biology
• Genetics

Background:

• Cryptic variation arises from phenotypic robustness to mutations.
• This hidden variation can influence evolution upon environmental or genetic changes.
• Its role in facilitating adaptation, particularly in complex organisms, remains under-explored.

Purpose of the Study:

• To investigate the role of cryptic genetic variation in accelerating evolutionary adaptation.
• To demonstrate that cryptic variation can contain pre-adapted genotypes beneficial in new environments.

Main Methods:

• Evolving populations of RNA enzymes with and without accumulated cryptic variation.
• Challenging populations with a new substrate to assess adaptation rates.
• Analyzing evolved RNA populations in genotype space to understand variation dynamics.

Main Results:

• Populations with cryptic variation adapted significantly faster to a new substrate.
• Detailed genotype analysis revealed exploration of new, adaptive genotypes facilitated by cryptic variation.
• Cryptic variation provided pre-adapted genotypes that became advantageous in the altered environment.

Conclusions:

• Cryptic genetic variation plays a positive role in adaptive evolution by enabling exploration of beneficial genotypes.
• Phenotypic robustness, leading to cryptic variation, can prime populations for rapid adaptation.
• Epistasis and robustness are key factors that can facilitate evolutionary adaptation through cryptic variation.