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Updated: Jun 5, 2025
07:55
High Throughput Yeast Strain Phenotyping with Droplet-Based RNA Sequencing
Published on: May 21, 2020
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A high-resolution two-step evolution experiment in yeast reveals a shift from pleiotropic to modular adaptation
Grant Kinsler1,2, Yuping Li3,4, Gavin Sherlock3
1Department of Biology, Stanford University, Stanford, California, United States of America.
Plos Biology
|December 5, 2024
Summary
Early evolution often involves large, pleiotropic mutations affecting multiple traits, particularly in signaling pathways. Later adaptation shifts to smaller, modular mutations, focusing on specific functions like respiration.
Area of Science:
- Evolutionary biology
- Genetics
- Microbial evolution
Background:
- Natural selection typically drives slow, gradual evolution via small mutations.
- However, early adaptive mutations often yield substantial fitness gains and affect multiple traits (pleiotropy).
Purpose of the Study:
- Investigate if pleiotropic mutations are common throughout adaptation or limited to early stages.
- Determine if early pleiotropic mutations target key signaling pathways.
Main Methods:
- Conducted barcoded second-step evolution experiments in yeast.
- Initiated experiments from five identified first-step mutations.
- Isolated and analyzed hundreds of second-step mutations for fitness, performance, and whole-genome sequencing.
Main Results:
- First-step mutations showed pleiotropic adaptation (improving fermentation and respiration).
- Second-step mutations shifted to modular adaptation (improving respiration, rarely fermentation).
- Molecular basis shifted from signaling genes to respiration/mitochondrial genes.
Conclusions:
- Signaling pathway genes likely provide early, large, pleiotropic benefits.
- Exhaustion of these genes leads to gradual adaptation with smaller, modular mutations.
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