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Abstract Evolutionary biologists have long sought to understand what factors affect the repeatability of adaptive outcomes. To better understand the role of temperature in determining the repeatability of adaptive trajectories, we evolved populations of different genotypes of the ciliateTetrahymena thermophilaat low and high temperatures and followed changes in growth rate over 6,500 generations. As expected, growth rate increased with a decelerating rate for all populations; however, there were differences in the patterns of evolution at the two temperatures. The growth rates of the different genotypes tended to converge as evolution proceeded at both temperatures, but this convergence was quicker and more pronounced at the higher temperature. Additionally, over the first 4,000 generations we found greater repeatability of evolution, in terms of change in growth rate, among replicates of the same genotype at the higher temperature. Finally, we found limited evidence of trade‐offs in fitness between temperatures, and an asymmetry in the correlated responses, whereby evolution in a high temperature increases growth rate at the lower temperature significantly more than the reverse. These results demonstrate the importance of temperature in determining the repeatability of evolutionary trajectories for the eukaryotic microbeTetrahymena thermophilaand may provide clues to how temperature affects evolution more generally.
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Experimental Evolution in Tetrahymena
Experimental evolution has provided novel insight into a wide array of biological processes. Species in the genus Tetrahymena are proving to be a highly useful system for studying a range of questions using experimental evolution. Their unusual genomic architecture, diversity of life history traits, importance as both predator and prey, and amenability to laboratory culture allow them to be studied in a variety of contexts. In this paper, we review what we are learning from experimental evolution with Tetrahymena about mutation, adaptation, and eco-evolutionary dynamics. We predict that future experimental evolution studies using Tetrahyemena will continue to shed new light on these processes.
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- Award ID(s):
- 1911449
- PAR ID:
- 10321284
- Date Published:
- Journal Name:
- Microorganisms
- Volume:
- 10
- Issue:
- 2
- ISSN:
- 2076-2607
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/microorganisms10020414
