Experimental evolution reveals contrasting adaptive landscapes in lab and field environments
- 1Department of Earth Sciences, Southern Methodist University, Dallas, Texas, USA
- 2Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
- 3Department of Earth System Sciences, University of California, Irvine, California, USA
Abstract
Experimental evolution is widely used to infer microbial responses to environmental change, yet most laboratory studies impose constant, well-mixed conditions that differ fundamentally from fluctuating, spatially structured field environments. We compared genomic evolution in the leaf litter-associated bacterium Curtobacterium strain MMLR14_002 under control and warming treatments in laboratory culture and in a complementary field experiment. Laboratory-derived isolates accumulated more mutations per genome and exhibited stronger locus-level parallelism, with mutations recurring in a small number of coding loci. Field-derived isolates accumulated fewer mutations per genome, and these mutations rarely occurred in the same coding loci across replicate populations. Instead, field isolates exhibited a higher proportion of intergenic mutations, with mutations recurring in the same intergenic regions across independent field deployments. When coding mutations were detected in the field, they were distributed across functionally diffuse targets and more often involved metabolic pathways than the core cellular processes repeatedly targeted during laboratory evolution. Warming itself did not consistently influence mutation accumulation or the genomic distribution of mutations; instead, laboratory and field contexts primarily shaped the accumulation, targets, and repeatability of genomic change. These results suggest that laboratory thermal evolution identifies adaptive routes favored under sustained selection but may overestimate coding-level parallelism under heterogeneous field conditions. Bridging laboratory and field evolution will likely require experimental designs that incorporate temporal variability and spatial heterogeneity characteristic of natural systems.
IMPORTANCE: A central goal of experimental evolution is to infer how microbes evolve in nature from laboratory studies. Here, we evaluate this assumption by comparing genomic evolution of a leaf litter-associated Curtobacterium strain in laboratory and field warming experiments to identify broad patterns rather than isolate the contribution of any single environmental factor. We find that the strong parallelism at coding loci observed under laboratory conditions is reduced in the field, while mutations recurring in the same intergenic regions across field deployments suggest that parallel evolution in nature may more often involve regulatory noncoding regions rather than coding targets. These results show that environmental context reshapes adaptive landscapes and may limit the parallelism of coding-level genomic responses inferred from homogeneous laboratory conditions.
Related
- Agronomic Performance of Microbial Inoculation Strategies in Soybean, Maize and Wheat Across Contrasting Environments
- Thiamine availability and uptake in lake trout (Salvelinus namaycush) eggs and embryos: contrasting natural and artificial environments
- Spatial Reaction Norms of Barbary Macaques (Macaca sylvanus) in Response to Seasonal Resource Variation in Two Contrasting Landscapes
- Catchment structure and functioning mediates beaver activity in contrasting lowland agricultural landscapes
- One Core to Root them All: A Core Bacterial Community in Closely Related but Geographically Distant Mammillaria Species from Contrasting Environments.
BibTeX
@article{chase2026experimental,
title = {{Experimental evolution reveals contrasting adaptive landscapes in lab and field environments}},
author = {Alexander B. Chase and Zhao Wang and Claudia Weihe and Steven D. Allison and Jennifer B. H. Martiny},
journal = {mBio},
year = {2026},
month = sep,
doi = {10.1128/mbio.01700-26},
url = {https://doi.org/10.1128/mbio.01700-26},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Experimental evolution reveals contrasting adaptive landscapes in lab and field environments
AU - Alexander B. Chase
AU - Zhao Wang
AU - Claudia Weihe
AU - Steven D. Allison
AU - Jennifer B. H. Martiny
PY - 2026
DA - 2026/09/08
JO - mBio
DO - 10.1128/mbio.01700-26
UR - https://doi.org/10.1128/mbio.01700-26
AB - Experimental evolution is widely used to infer microbial responses to environmental change, yet most laboratory studies impose constant, well-mixed conditions that differ fundamentally from fluctuating, spatially structured field environments. We compared genomic evolution in the leaf litter-associated bacterium Curtobacterium strain MMLR14_002 under control and warming treatments in laboratory culture and in a complementary field experiment. Laboratory-derived isolates accumulated more mutations per genome and exhibited stronger locus-level parallelism, with mutations recurring in a small number of coding loci. Field-derived isolates accumulated fewer mutations per genome, and these mutations rarely occurred in the same coding loci across replicate populations. Instead, field isolates exhibited a higher proportion of intergenic mutations, with mutations recurring in the same intergenic regions across independent field deployments. When coding mutations were detected in the field, they were distributed across functionally diffuse targets and more often involved metabolic pathways than the core cellular processes repeatedly targeted during laboratory evolution. Warming itself did not consistently influence mutation accumulation or the genomic distribution of mutations; instead, laboratory and field contexts primarily shaped the accumulation, targets, and repeatability of genomic change. These results suggest that laboratory thermal evolution identifies adaptive routes favored under sustained selection but may overestimate coding-level parallelism under heterogeneous field conditions. Bridging laboratory and field evolution will likely require experimental designs that incorporate temporal variability and spatial heterogeneity characteristic of natural systems. IMPORTANCE: A central goal of experimental evolution is to infer how microbes evolve in nature from laboratory studies. Here, we evaluate this assumption by comparing genomic evolution of a leaf litter-associated Curtobacterium strain in laboratory and field warming experiments to identify broad patterns rather than isolate the contribution of any single environmental factor. We find that the strong parallelism at coding loci observed under laboratory conditions is reduced in the field, while mutations recurring in the same intergenic regions across field deployments suggest that parallel evolution in nature may more often involve regulatory noncoding regions rather than coding targets. These results show that environmental context reshapes adaptive landscapes and may limit the parallelism of coding-level genomic responses inferred from homogeneous laboratory conditions.
SN - 2150-7511
ER -