Copy number variation facilitates rapid toggling between ecological strategies

Area of Science:

• Evolutionary biology
• Genomics
• Ecology

Background:

• Understanding how different mutation types influence ecological strategy is crucial.
• Copy number variants (CNVs) can alter gene dosage, but their adaptive role remains unclear.
• SNVs and CNVs are mutation types affecting gene dosage.

Purpose of the Study:

• To investigate whether CNVs confer unique adaptive advantages.
• To determine if CNVs mediate adaptive tracking in fluctuating environments.
• To establish a framework for predicting ecological strategy from genome structure.

Main Methods:

• Utilized a dual-fluorescent CNV reporter system in *Saccharomyces cerevisiae*.
• Tracked CNV dynamics under static and fluctuating nitrogen limitation.
• Analyzed over 3,000 yeast genomes to identify CNV signatures.

Main Results:

• CNVs did not track environmental changes but acted as reversible toggles.
• CNV copy number ratios, not absolute counts, predicted ecological strategy (specialist vs. generalist).
• Static environments favored specialists; fluctuating environments favored generalists.

Conclusions:

• CNV ratios serve as a molecular signature of niche breadth.
• This framework generalizes the prediction of ecological strategy from genome structure.
• Specialist CNV signatures were found exclusively in domesticated yeast strains.