1
|
Siddiq MA, Duveau F, Wittkopp PJ. Plasticity and environment-specific relationships between gene expression and fitness in Saccharomyces cerevisiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589130. [PMID: 38659876 PMCID: PMC11042213 DOI: 10.1101/2024.04.12.589130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Phenotypic evolution is shaped by interactions between organisms and their environments. The environment influences how an organism's genotype determines its phenotype and how this phenotype affects its fitness. To better understand this dual role of the environment in the production and selection of phenotypic variation, we empirically determined and compared the genotype-phenotype-fitness relationship for mutant strains of the budding yeast Saccharomyces cerevisiae in four environments. Specifically, we measured how mutations in the promoter of the metabolic gene TDH3 modified its expression level and affected its growth on media with four different carbon sources. In each environment, we observed a clear relationship between TDH3 expression level and fitness, but this relationship differed among environments. Genetic variants with similar effects on TDH3 expression in different environments often had different effects on fitness and vice versa. Such environment-specific relationships between phenotype and fitness can shape the evolution of phenotypic plasticity. The set of mutants we examined also allowed us to compare the effects of mutations disrupting binding sites for key transcriptional regulators and the TATA box, which is part of the core promoter sequence. Mutations disrupting the binding sites for the transcription factors had more variable effects on expression among environments than mutations disrupting the TATA box, yet mutations with the most environmentally variable effects on fitness were located in the TATA box. This observation suggests that mutations affecting different molecular mechanisms are likely to contribute unequally to regulatory sequence evolution in changing environments.
Collapse
Affiliation(s)
- Mohammad A. Siddiq
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan
- Authors contributed equally to this work
| | - Fabien Duveau
- Department of Ecology and Evolutionary Biology, University of Michigan
- Laboratory of Biology and Modeling of the Cell, Ecole Normale Supérieure de Lyon, CNRS, Université Claude Bernard Lyon, Université de Lyon, France
- Authors contributed equally to this work
| | - Patricia J. Wittkopp
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan
- Department of Ecology and Evolutionary Biology, University of Michigan
| |
Collapse
|
2
|
Erkosar B, Dupuis C, Cavigliasso F, Savary L, Kremmer L, Gallart-Ayala H, Ivanisevic J, Kawecki TJ. Evolutionary adaptation to juvenile malnutrition impacts adult metabolism and impairs adult fitness in Drosophila. eLife 2023; 12:e92465. [PMID: 37847744 PMCID: PMC10637773 DOI: 10.7554/elife.92465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 10/12/2023] [Indexed: 10/19/2023] Open
Abstract
Juvenile undernutrition has lasting effects on adult metabolism of the affected individuals, but it is unclear how adult physiology is shaped over evolutionary time by natural selection driven by juvenile undernutrition. We combined RNAseq, targeted metabolomics, and genomics to study the consequences of evolution under juvenile undernutrition for metabolism of reproductively active adult females of Drosophila melanogaster. Compared to Control populations maintained on standard diet, Selected populations maintained for over 230 generations on a nutrient-poor larval diet evolved major changes in adult gene expression and metabolite abundance, in particular affecting amino acid and purine metabolism. The evolved differences in adult gene expression and metabolite abundance between Selected and Control populations were positively correlated with the corresponding differences previously reported for Selected versus Control larvae. This implies that genetic variants affect both stages similarly. Even when well fed, the metabolic profile of Selected flies resembled that of flies subject to starvation. Finally, Selected flies had lower reproductive output than Controls even when both were raised under the conditions under which the Selected populations evolved. These results imply that evolutionary adaptation to juvenile undernutrition has large pleiotropic consequences for adult metabolism, and that they are costly rather than adaptive for adult fitness. Thus, juvenile and adult metabolism do not appear to evolve independently from each other even in a holometabolous species where the two life stages are separated by a complete metamorphosis.
Collapse
Affiliation(s)
- Berra Erkosar
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Cindy Dupuis
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Fanny Cavigliasso
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Loriane Savary
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Laurent Kremmer
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| | - Hector Gallart-Ayala
- Metabolomics Unit, Faculty of Biology and Medicine, University of LausanneLausanneSwitzerland
| | - Julijana Ivanisevic
- Metabolomics Unit, Faculty of Biology and Medicine, University of LausanneLausanneSwitzerland
| | - Tadeusz J Kawecki
- Department of Ecology and Evolution, University of LausanneLausanneSwitzerland
| |
Collapse
|
3
|
Chen P, Zhang J. Transcriptomic analysis reveals the rareness of genetic assimilation of gene expression in environmental adaptations. SCIENCE ADVANCES 2023; 9:eadi3053. [PMID: 37756399 PMCID: PMC10530075 DOI: 10.1126/sciadv.adi3053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023]
Abstract
Genetic assimilation is the evolutionary process by which an environmentally induced phenotype becomes genetically encoded and constitutive. Genetic assimilation has been proposed as a concluding step in environmental adaptation, but its prevalence has not been systematically investigated. Analyzing transcriptomic data collected upon reciprocal transplant, we address this question in the experimental evolution, domestication, or natural evolution of seven diverse species. We find that genetic assimilation of environment-induced gene expression is the exception rather than the rule and that substantially more genes retain than lose their expression plasticity upon organismal adaptations to new environments. The probability of genetic assimilation of gene expression decreases with the expression level and number of transcription factors controlling the gene, suggesting that genetic assimilation results primarily from passive losses of gene regulations that are not mutationally robust. Hence, for gene expression, our findings argue against the purported generality or importance of genetic assimilation to environmental adaptation.
Collapse
Affiliation(s)
- Piaopiao Chen
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | | |
Collapse
|
4
|
Ballinger MA, Mack KL, Durkin SM, Riddell EA, Nachman MW. Environmentally robust cis-regulatory changes underlie rapid climatic adaptation. Proc Natl Acad Sci U S A 2023; 120:e2214614120. [PMID: 37725649 PMCID: PMC10523592 DOI: 10.1073/pnas.2214614120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 07/26/2023] [Indexed: 09/21/2023] Open
Abstract
Changes in gene expression are thought to play a major role in adaptive evolution. While it is known that gene expression is highly sensitive to the environment, very few studies have determined the influence of genetic and environmental effects on adaptive gene expression differences in natural populations. Here, we utilize allele-specific expression to characterize cis and trans gene regulatory divergence in temperate and tropical house mice in two metabolic tissues under two thermal conditions. First, we show that gene expression divergence is pervasive between populations and across thermal conditions, with roughly 5 to 10% of genes exhibiting genotype-by-environment interactions. Second, we found that most expression divergence was due to cis-regulatory changes that were stable across temperatures. In contrast, patterns of expression plasticity were largely attributable to trans-effects, which showed greater sensitivity to temperature. Nonetheless, we found a small subset of temperature-dependent cis-regulatory changes, thereby identifying loci underlying expression plasticity. Finally, we performed scans for selection in wild house mice to identify genomic signatures of rapid adaptation. Genomic outliers were enriched in genes with evidence for cis-regulatory divergence. Notably, these genes were associated with phenotypes that affected body weight and metabolism, suggesting that cis-regulatory changes are a possible mechanism for adaptive body size evolution between populations. Our results show that gene expression plasticity, largely controlled in trans, may facilitate the colonization of new environments, but that evolved changes in gene expression are largely controlled in cis, illustrating the genetic and nongenetic mechanisms underlying the establishment of populations in new environments.
Collapse
Affiliation(s)
- Mallory A. Ballinger
- Museum of Vertebrate Zoology, University of California, Berkeley, CA94720
- Department of Integrative Biology, University of California, Berkeley, CA94720
- Department of Biology, Utah State University, Logan, UT84322
| | - Katya L. Mack
- Department of Biology, Stanford University, Stanford, CA94305
| | - Sylvia M. Durkin
- Museum of Vertebrate Zoology, University of California, Berkeley, CA94720
- Department of Integrative Biology, University of California, Berkeley, CA94720
| | - Eric A. Riddell
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA50011
| | - Michael W. Nachman
- Museum of Vertebrate Zoology, University of California, Berkeley, CA94720
- Department of Integrative Biology, University of California, Berkeley, CA94720
| |
Collapse
|
5
|
Cavigliasso F, Savary L, Spangenberg JE, Gallart-Ayala H, Ivanisevic J, Kawecki TJ. Experimental evolution of metabolism under nutrient restriction: enhanced amino acid catabolism and a key role of branched-chain amino acids. Evol Lett 2023; 7:273-284. [PMID: 37475747 PMCID: PMC10355184 DOI: 10.1093/evlett/qrad018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/04/2023] [Accepted: 04/24/2023] [Indexed: 07/22/2023] Open
Abstract
Periodic food shortage is a common ecological stressor for animals, likely to drive physiological and metabolic adaptations to alleviate its consequences, particularly for juveniles that have no option but to continue to grow and develop despite undernutrition. Here we study changes in metabolism associated with adaptation to nutrient shortage, evolved by replicate Drosophila melanogaster populations maintained on a nutrient-poor larval diet for over 240 generations. In a factorial metabolomics experiment we showed that both phenotypic plasticity and genetically-based adaptation to the poor diet involved wide-ranging changes in metabolite abundance; however, the plastic response did not predict the evolutionary change. Compared to nonadapted larvae exposed to the poor diet for the first time, the adapted larvae showed lower levels of multiple free amino acids in their tissues-and yet they grew faster. By quantifying accumulation of the nitrogen stable isotope 15N we show that adaptation to the poor diet led to an increased use of amino acids for energy generation. This apparent "waste" of scarce amino acids likely results from the trade-off between acquisition of dietary amino acids and carbohydrates observed in these populations. The three branched-chain amino acids (leucine, isoleucine, and valine) showed a unique pattern of depletion in adapted larvae raised on the poor diet. A diet supplementation experiment demonstrated that these amino acids are limiting for growth on the poor diet, suggesting that their low levels resulted from their expeditious use for protein synthesis. These results demonstrate that selection driven by nutrient shortage not only promotes improved acquisition of limiting nutrients, but also has wide-ranging effects on how the nutrients are used. They also show that the abundance of free amino acids in the tissues does not, in general, reflect the nutritional condition and growth potential of an animal.
Collapse
Affiliation(s)
- Fanny Cavigliasso
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Loriane Savary
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Jorge E Spangenberg
- Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
| | - Hector Gallart-Ayala
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Julijana Ivanisevic
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Tadeusz J Kawecki
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
6
|
Walter GM, Clark J, Terranova D, Cozzolino S, Cristaudo A, Hiscock SJ, Bridle J. Hidden genetic variation in plasticity provides the potential for rapid adaptation to novel environments. THE NEW PHYTOLOGIST 2023; 239:374-387. [PMID: 36651081 DOI: 10.1111/nph.18744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 01/02/2023] [Indexed: 06/02/2023]
Abstract
Rapid environmental change is forcing populations into environments where plasticity will no longer maintain fitness. When populations are exposed to novel environments, evolutionary theory predicts that genetic variation in fitness will increase and should be associated with genetic differences in plasticity. If true, then genetic variation in plasticity can increase adaptive potential in novel environments, and population persistence via evolutionary rescue is more likely. To test whether genetic variation in fitness increases in novel environments and is associated with plasticity, we transplanted 8149 clones of 314 genotypes of a Sicilian daisy (Senecio chrysanthemifolius) within and outside its native range, and quantified genetic variation in fitness, and plasticity in leaf traits and gene expression. Although mean fitness declined by 87% in the novel environment, genetic variance in fitness increased threefold and was correlated with plasticity in leaf traits. High fitness genotypes showed greater plasticity in gene expression, but lower plasticity in most leaf traits. Interestingly, genotypes with the highest fitness in the novel environment had the lowest fitness at the native site. These results suggest that standing genetic variation in plasticity could help populations to persist and adapt to novel environments, despite remaining hidden in native environments.
Collapse
Affiliation(s)
- Greg M Walter
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - James Clark
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
- Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Delia Terranova
- Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, 95128, Italy
- Department of Biology, University of Naples Federico II, Naples, 80126, Italy
| | - Salvatore Cozzolino
- Department of Biology, University of Naples Federico II, Naples, 80126, Italy
| | - Antonia Cristaudo
- Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, 95128, Italy
| | - Simon J Hiscock
- Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Jon Bridle
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
- Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK
| |
Collapse
|
7
|
Gupta S, Harkess A, Soble A, Van Etten M, Leebens-Mack J, Baucom RS. Interchromosomal linkage disequilibrium and linked fitness cost loci associated with selection for herbicide resistance. THE NEW PHYTOLOGIST 2023; 238:1263-1277. [PMID: 36721257 DOI: 10.1111/nph.18782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
The adaptation of weeds to herbicide is both a significant problem in agriculture and a model of rapid adaptation. However, significant gaps remain in our knowledge of resistance controlled by many loci and the evolutionary factors that influence the maintenance of resistance. Here, using herbicide-resistant populations of the common morning glory (Ipomoea purpurea), we perform a multilevel analysis of the genome and transcriptome to uncover putative loci involved in nontarget-site herbicide resistance (NTSR) and to examine evolutionary forces underlying the maintenance of resistance in natural populations. We found loci involved in herbicide detoxification and stress sensing to be under selection and confirmed that detoxification is responsible for glyphosate (RoundUp) resistance using a functional assay. We identified interchromosomal linkage disequilibrium (ILD) among loci under selection reflecting either historical processes or additive effects leading to the resistance phenotype. We further identified potential fitness cost loci that were strongly linked to resistance alleles, indicating the role of genetic hitchhiking in maintaining the cost. Overall, our work suggests that NTSR glyphosate resistance in I. purpurea is conferred by multiple genes which are potentially maintained through generations via ILD, and that the fitness cost associated with resistance in this species is likely a by-product of genetic hitchhiking.
Collapse
Affiliation(s)
- Sonal Gupta
- Ecology and Evolutionary Biology Department, University of Michigan, 4034 Biological Sciences Building, Ann Arbor, MI, 48109, USA
- Center for Genomics and Systems Biology, New York University, New York, NY, 10003, USA
| | - Alex Harkess
- Department of Crop, Soil and Environmental Sciences, Auburn University, Auburn, AL, 36849, USA
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, 35806, USA
| | - Anah Soble
- Ecology and Evolutionary Biology Department, University of Michigan, 4034 Biological Sciences Building, Ann Arbor, MI, 48109, USA
| | - Megan Van Etten
- Biology Department, Pennsylvania State University, Dunmore, PA, 18512, USA
| | - James Leebens-Mack
- Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
| | - Regina S Baucom
- Ecology and Evolutionary Biology Department, University of Michigan, 4034 Biological Sciences Building, Ann Arbor, MI, 48109, USA
| |
Collapse
|
8
|
Wood DP, Holmberg JA, Osborne OG, Helmstetter AJ, Dunning LT, Ellison AR, Smith RJ, Lighten J, Papadopulos AST. Genetic assimilation of ancestral plasticity during parallel adaptation to zinc contamination in Silene uniflora. Nat Ecol Evol 2023; 7:414-423. [PMID: 36702857 PMCID: PMC9998271 DOI: 10.1038/s41559-022-01975-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 12/12/2022] [Indexed: 01/27/2023]
Abstract
Phenotypic plasticity in ancestral populations is hypothesized to facilitate adaptation, but evidence is piecemeal and often contradictory. Further, whether ancestral plasticity increases the probability of parallel adaptive changes has not been explored. The most general finding is that ancestral responses to a new environment are reversed following adaptation (known as reversion). We investigated the contribution of ancestral plasticity to adaptive evolution of gene expression in two independently evolved lineages of zinc-tolerant Silene uniflora. We found that the general pattern of reversion is driven by the absence of a widespread stress response in zinc-adapted plants compared with zinc-sensitive plants. We show that ancestral plasticity that moves expression closer to the optimum value in the new environment influences the evolution of gene expression among genes that are likely to be involved in adaptation and increases the chance that genes are recruited repeatedly during adaptation. However, despite convergence in gene expression levels between independently adapted lineages, ancestral plasticity does not influence how similar expression values of adaptive genes become. Surprisingly, we also observed that ancestral plasticity that increases fitness often becomes genetically determined and fixed, that is, genetically assimilated. These results emphasize the important role of ancestral plasticity in parallel adaptation.
Collapse
Affiliation(s)
- Daniel P Wood
- Molecular Ecology and Evolution Bangor, School of Natural Sciences, Bangor University, Environment Centre Wales, Bangor, UK
| | - Jon A Holmberg
- Molecular Ecology and Evolution Bangor, School of Natural Sciences, Bangor University, Environment Centre Wales, Bangor, UK
| | - Owen G Osborne
- Molecular Ecology and Evolution Bangor, School of Natural Sciences, Bangor University, Environment Centre Wales, Bangor, UK
| | - Andrew J Helmstetter
- Fondation pour la Recherche sur la Biodiversité - Centre for the Synthesis and Analysis of Biodiversity, Institut Bouisson Bertrand, Montpellier, France
| | - Luke T Dunning
- Ecology and Evolutionary Biology, School of Biosciences, Sheffield, UK
| | - Amy R Ellison
- Molecular Ecology and Evolution Bangor, School of Natural Sciences, Bangor University, Environment Centre Wales, Bangor, UK
| | | | - Jackie Lighten
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Alexander S T Papadopulos
- Molecular Ecology and Evolution Bangor, School of Natural Sciences, Bangor University, Environment Centre Wales, Bangor, UK.
| |
Collapse
|
9
|
Li B, Gschwend AR, Hovick SM, Gutek A, McHale L, Harrison SK, Regnier EE. Evolution of weedy giant ragweed ( Ambrosia trifida): Multiple origins and gene expression variability facilitates weediness. Ecol Evol 2022; 12:e9590. [PMID: 36514541 PMCID: PMC9731915 DOI: 10.1002/ece3.9590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 11/16/2022] [Indexed: 12/13/2022] Open
Abstract
Agricultural weeds may originate from wild populations, but the origination patterns and genetics underlying this transition remain largely unknown. Analysis of weedy-wild paired populations from independent locations may provide evidence to identify key genetic variation contributing to this adaptive shift. We performed genetic variation and expression analyses on transcriptome data from 67 giant ragweed samples collected from different locations in Ohio, Iowa, and Minnesota and found geographically separated weedy populations likely originated independently from their adjacent wild populations, but subsequent spreading of weedy populations also occurred locally. By using eight closely related weedy-wild paired populations, we identified thousands of unique transcripts in weedy populations that reflect shared or specific functions corresponding, respectively, to both convergently evolved and population-specific weediness processes. In addition, differential expression of specific groups of genes was detected between weedy and wild giant ragweed populations using gene expression diversity and gene co-expression network analyses. Our study suggests an integrated route of weedy giant ragweed origination, consisting of independent origination combined with the subsequent spreading of certain weedy populations, and provides several lines of evidence to support the hypothesis that gene expression variability plays a key role in the evolution of weedy species.
Collapse
Affiliation(s)
- Bo Li
- Department of Horticulture and Crop SciencesThe Ohio State UniversityColumbusOhioUSA
| | - Andrea R. Gschwend
- Department of Horticulture and Crop SciencesThe Ohio State UniversityColumbusOhioUSA
| | - Stephen M. Hovick
- Department of Evolution, Ecology and Organismal BiologyThe Ohio State UniversityColumbusOhioUSA
| | - Amanda Gutek
- Department of Horticulture and Crop SciencesThe Ohio State UniversityColumbusOhioUSA
| | - Leah McHale
- Department of Horticulture and Crop SciencesThe Ohio State UniversityColumbusOhioUSA
| | - S. Kent Harrison
- Department of Horticulture and Crop SciencesThe Ohio State UniversityColumbusOhioUSA
| | - Emilie E. Regnier
- Department of Horticulture and Crop SciencesThe Ohio State UniversityColumbusOhioUSA
| |
Collapse
|
10
|
Huang Y, Lack JB, Hoppel GT, Pool JE. Gene Regulatory Evolution in Cold-Adapted Fly Populations Neutralizes Plasticity and May Undermine Genetic Canalization. Genome Biol Evol 2022; 14:evac050. [PMID: 35380655 PMCID: PMC9017818 DOI: 10.1093/gbe/evac050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2022] [Indexed: 11/12/2022] Open
Abstract
The relationships between adaptive evolution, phenotypic plasticity, and canalization remain incompletely understood. Theoretical and empirical studies have made conflicting arguments on whether adaptive evolution may enhance or oppose the plastic response. Gene regulatory traits offer excellent potential to study the relationship between plasticity and adaptation, and they can now be studied at the transcriptomic level. Here, we take advantage of three closely related pairs of natural populations of Drosophila melanogaster from contrasting thermal environments that reflect three separate instances of cold tolerance evolution. We measure the transcriptome-wide plasticity in gene expression levels and alternative splicing (intron usage) between warm and cold laboratory environments. We find that suspected adaptive changes in both gene expression and alternative splicing tend to neutralize the ancestral plastic response. Further, we investigate the hypothesis that adaptive evolution can lead to decanalization of selected gene regulatory traits. We find strong evidence that suspected adaptive gene expression (but not splicing) changes in cold-adapted populations are more vulnerable to the genetic perturbation of inbreeding than putatively neutral changes. We find some evidence that these patterns may reflect a loss of genetic canalization accompanying adaptation, although other processes including hitchhiking recessive deleterious variants may contribute as well. Our findings augment our understanding of genetic and environmental effects on gene regulation in the context of adaptive evolution.
Collapse
Affiliation(s)
- Yuheng Huang
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Justin B Lack
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA
| | - Grant T Hoppel
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - John E Pool
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| |
Collapse
|