Reciprocal Sign Epistasis between Adaptive Mutations Causes a Rugged Fitness Landscape
Author Information
Author(s): Kvitek Daniel J., Sherlock Gavin
Primary Institution: Stanford University
Hypothesis
Does reciprocal sign epistasis between adaptive mutations create barriers to adaptation in yeast?
Conclusion
The study shows that reciprocal sign epistasis between mutations in the genes MTH1 and HXT6/HXT7 creates a rugged fitness landscape that constrains adaptation.
Supporting Evidence
- Mutations in MTH1 and HXT6/HXT7 arose multiple times independently during the experiment.
- The double mutant of MTH1 and HXT6/HXT7 was less fit than either single mutant.
- Reciprocal sign epistasis was observed, indicating that these mutations cannot coexist in the same lineage.
- Fitness valleys were identified that hindered adaptation between different peaks in the fitness landscape.
Takeaway
When yeast adapt to low glucose, some mutations help them, but if two specific mutations happen together, they actually make the yeast less fit, like trying to carry two heavy backpacks at once.
Methodology
The study used whole-genome sequencing and competitive fitness assays to analyze mutations in yeast.
Limitations
The study may not account for all possible mutations and their interactions in the fitness landscape.
Participant Demographics
The study focused on asexual populations of Saccharomyces cerevisiae.
Statistical Information
P-Value
p<0.05
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
Want to read the original?
Access the complete publication on the publisher's website