1
|
Bitter MC, Berardi S, Oken H, Huynh A, Lappo E, Schmidt P, Petrov DA. Continuously fluctuating selection reveals fine granularity of adaptation. Nature 2024:10.1038/s41586-024-07834-x. [PMID: 39143223 DOI: 10.1038/s41586-024-07834-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 07/16/2024] [Indexed: 08/16/2024]
Abstract
Temporally fluctuating environmental conditions are a ubiquitous feature of natural habitats. Yet, how finely natural populations adaptively track fluctuating selection pressures via shifts in standing genetic variation is unknown1,2. Here we generated genome-wide allele frequency data every 1-2 generations from a genetically diverse population of Drosophila melanogaster in extensively replicated field mesocosms from late June to mid-December (a period of approximately 12 total generations). Adaptation throughout the fundamental ecological phases of population expansion, peak density and collapse was underpinned by extremely rapid, parallel changes in genomic variation across replicates. Yet, the dominant direction of selection fluctuated repeatedly, even within each of these ecological phases. Comparing patterns of change in allele frequency to an independent dataset procured from the same experimental system demonstrated that the targets of selection are predictable across years. In concert, our results reveal a fitness relevance of standing variation that is likely to be masked by inference approaches based on static population sampling or insufficiently resolved time-series data. We propose that such fine-scaled, temporally fluctuating selection may be an important force contributing to the maintenance of functional genetic variation in natural populations and an important stochastic force impacting genome-wide patterns of diversity at linked neutral sites, akin to genetic draft.
Collapse
Affiliation(s)
- M C Bitter
- Department of Biology, Stanford University, Stanford, CA, USA.
| | - S Berardi
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - H Oken
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - A Huynh
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Egor Lappo
- Department of Biology, Stanford University, Stanford, CA, USA
| | - P Schmidt
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
| | - D A Petrov
- Department of Biology, Stanford University, Stanford, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
| |
Collapse
|
2
|
Mayekar HV, Rajpurohit S. No single rescue recipe: genome complexities modulate insect response to climate change. CURRENT OPINION IN INSECT SCIENCE 2024; 64:101220. [PMID: 38848812 DOI: 10.1016/j.cois.2024.101220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/08/2024] [Accepted: 05/31/2024] [Indexed: 06/09/2024]
Abstract
Declines in insect populations have gained formidable attention. Given their crucial role in the ecosystem, the causes of declining insect populations must be investigated. However, the insect clade has been associated with low extinction and high diversification rates. It is unlikely that insects underwent mass extinctions in the past. However, the pace of current climate change could make insect populations vulnerable to extinction. We propose genome size (GS) and transposable elements (TEs) to be rough estimates to assess extinction risk. Larger GS and/or proliferating TEs have been associated with adaptation in rapid climate change scenarios. We speculate that unstable, stressful environmental conditions are strongly associated with GS and TE expansion, which could be further correlated with adaptations. Alternately, stressful conditions trigger TE bursts that are not purged in smaller populations. GS and TE loads could be indicators of small effective populations in the wild, likely experiencing bottlenecks or drastic climatic perturbations, which calls for an urgent assessment of extinction risk.
Collapse
Affiliation(s)
- Harshad Vijay Mayekar
- Biological and Life Sciences, School of Arts of Sciences, Ahmedabad University, Ahmedabad 380009, India.
| | - Subhash Rajpurohit
- Biological and Life Sciences, School of Arts of Sciences, Ahmedabad University, Ahmedabad 380009, India.
| |
Collapse
|
3
|
Lynch M, Wei W, Ye Z, Pfrender M. The genome-wide signature of short-term temporal selection. Proc Natl Acad Sci U S A 2024; 121:e2307107121. [PMID: 38959040 PMCID: PMC11252749 DOI: 10.1073/pnas.2307107121] [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: 05/01/2023] [Accepted: 06/03/2024] [Indexed: 07/04/2024] Open
Abstract
Despite evolutionary biology's obsession with natural selection, few studies have evaluated multigenerational series of patterns of selection on a genome-wide scale in natural populations. Here, we report on a 10-y population-genomic survey of the microcrustacean Daphnia pulex. The genome sequences of [Formula: see text]800 isolates provide insights into patterns of selection that cannot be obtained from long-term molecular-evolution studies, including the following: the pervasiveness of near quasi-neutrality across the genome (mean net selection coefficients near zero, but with significant temporal variance about the mean, and little evidence of positive covariance of selection across time intervals); the preponderance of weak positive selection operating on minor alleles; and a genome-wide distribution of numerous small linkage islands of observable selection influencing levels of nucleotide diversity. These results suggest that interannual fluctuating selection is a major determinant of standing levels of variation in natural populations, challenge the conventional paradigm for interpreting patterns of nucleotide diversity and divergence, and motivate the need for the further development of theoretical expressions for the interpretation of population-genomic data.
Collapse
Affiliation(s)
- Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ85287
| | - Wen Wei
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ85287
| | - Zhiqiang Ye
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan430079, China
| | - Michael Pfrender
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN46556
| |
Collapse
|
4
|
Tralamazza SM, Gluck-Thaler E, Feurtey A, Croll D. Copy number variation introduced by a massive mobile element facilitates global thermal adaptation in a fungal wheat pathogen. Nat Commun 2024; 15:5728. [PMID: 38977688 PMCID: PMC11231334 DOI: 10.1038/s41467-024-49913-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 06/25/2024] [Indexed: 07/10/2024] Open
Abstract
Copy number variation (CNV) can drive rapid evolution in changing environments. In microbial pathogens, such adaptation is a key factor underpinning epidemics and colonization of new niches. However, the genomic determinants of such adaptation remain poorly understood. Here, we systematically investigate CNVs in a large genome sequencing dataset spanning a worldwide collection of 1104 genomes from the major wheat pathogen Zymoseptoria tritici. We found overall strong purifying selection acting on most CNVs. Genomic defense mechanisms likely accelerated gene loss over episodes of continental colonization. Local adaptation along climatic gradients was likely facilitated by CNVs affecting secondary metabolite production and gene loss in general. One of the strongest loci for climatic adaptation is a highly conserved gene of the NAD-dependent Sirtuin family. The Sirtuin CNV locus localizes to an ~68-kb Starship mobile element unique to the species carrying genes highly expressed during plant infection. The element has likely lost the ability to transpose, demonstrating how the ongoing domestication of cargo-carrying selfish elements can contribute to selectable variation within populations. Our work highlights how standing variation in gene copy numbers at the global scale can be a major factor driving climatic and metabolic adaptation in microbial species.
Collapse
Affiliation(s)
- Sabina Moser Tralamazza
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
| | - Emile Gluck-Thaler
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Alice Feurtey
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Plant Pathology, D-USYS, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland.
| |
Collapse
|
5
|
Lasky JR, Takou M, Gamba D, Keitt TH. Estimating scale-specific and localized spatial patterns in allele frequency. Genetics 2024; 227:iyae082. [PMID: 38758968 PMCID: PMC11339607 DOI: 10.1093/genetics/iyae082] [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: 09/07/2023] [Revised: 09/07/2023] [Accepted: 04/28/2024] [Indexed: 05/19/2024] Open
Abstract
Characterizing spatial patterns in allele frequencies is fundamental to evolutionary biology because these patterns contain evidence of underlying processes. However, the spatial scales at which gene flow, changing selection, and drift act are often unknown. Many of these processes can operate inconsistently across space, causing nonstationary patterns. We present a wavelet approach to characterize spatial pattern in allele frequency that helps solve these problems. We show how our approach can characterize spatial patterns in relatedness at multiple spatial scales, i.e. a multilocus wavelet genetic dissimilarity. We also develop wavelet tests of spatial differentiation in allele frequency and quantitative trait loci (QTL). With simulation, we illustrate these methods under different scenarios. We also apply our approach to natural populations of Arabidopsis thaliana to characterize population structure and identify locally adapted loci across scales. We find, for example, that Arabidopsis flowering time QTL show significantly elevated genetic differentiation at 300-1,300 km scales. Wavelet transforms of allele frequencies offer a flexible way to reveal geographic patterns and underlying evolutionary processes.
Collapse
Affiliation(s)
- Jesse R Lasky
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Margarita Takou
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Diana Gamba
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Timothy H Keitt
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| |
Collapse
|
6
|
Lush J, Sgrò CM, Hall MD. Anticipating change: The impact of simulated seasonal heterogeneity on heat tolerances along a latitudinal cline. Ecology 2024; 105:e4359. [PMID: 38877760 DOI: 10.1002/ecy.4359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 01/18/2024] [Accepted: 02/19/2024] [Indexed: 06/16/2024]
Abstract
An understanding of thermal limits and variation across geographic regions is central to predicting how any population may respond to global change. Latitudinal clines, in particular, have been used to demonstrate that populations can be locally adapted to their own thermal environment and, as a result, not all populations will be equally impacted by an increase in temperature. But how robust are these signals of thermal adaptation to the other ecological challenges that animals commonly face in the wild? Seasonal changes in population density, food availability, or photoperiod are common ecological challenges that could disrupt patterns of thermal tolerance along a cline if each population differentially used these signals to anticipate future temperatures and adjust their thermal tolerances accordingly. In this study, we aimed to test the robustness of a cline in thermal tolerance to simulated signals of seasonal heterogeneity. Experimental animals were derived from clones of the Australian water flea, Daphnia carinata, sampled from nine distinct populations along a latitudinal transect in Eastern Australia. We then factorially combined summer (18 h light, 6 h dark) and winter (6 h light, 18 h dark) photoperiods with high (5 million algal cells individual-1 day-1) and low (1 million algal cells individual-1 day-1) food availabilities, before performing static heat shock assays to measure thermal tolerance. We found that the thermal tolerances of the clonal populations were sensitive to both measures of seasonal change. In general, higher food availability led to an increase in thermal tolerances, with the magnitude of the increase varying by clone. In contrast, a switch in photoperiod led to rank-order changes in thermal tolerances, with heat resistance increasing for some clones, and decreasing for others. Heat resistance, however, still declined with increasing latitude, irrespective of the manipulation of seasonal signals, with clones from northern populations always showing greater thermal resistance, most likely driven by adaptation to winter thermal conditions. While photoperiod and food availability can clearly shape thermal tolerances for specific populations, they are unlikely to overwhelm overarching signals of thermal adaptation, and thus, observed clines in heat resistance will likely have remained robust to these forms of seasonal heterogeneity.
Collapse
Affiliation(s)
- Jared Lush
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Carla M Sgrò
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Matthew D Hall
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| |
Collapse
|
7
|
Gutiérrez-Guerrero YT, Phifer-Rixey M, Nachman MW. Across two continents: The genomic basis of environmental adaptation in house mice (Mus musculus domesticus) from the Americas. PLoS Genet 2024; 20:e1011036. [PMID: 38968323 PMCID: PMC11253941 DOI: 10.1371/journal.pgen.1011036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 07/17/2024] [Accepted: 06/10/2024] [Indexed: 07/07/2024] Open
Abstract
Replicated clines across environmental gradients can be strong evidence of adaptation. House mice (Mus musculus domesticus) were introduced to the Americas by European colonizers and are now widely distributed from Tierra del Fuego to Alaska. Multiple aspects of climate, such as temperature, vary predictably across latitude in the Americas. Past studies of North American populations across latitudinal gradients provided evidence of environmental adaptation in traits related to body size, metabolism, and behavior and identified candidate genes using selection scans. Here, we investigate genomic signals of environmental adaptation on a second continent, South America, and ask whether there is evidence of parallel adaptation across multiple latitudinal transects in the Americas. We first identified loci across the genome showing signatures of selection related to climatic variation in mice sampled across a latitudinal transect in South America, accounting for neutral population structure. Consistent with previous results, most candidate SNPs were in putatively regulatory regions. Genes that contained the most extreme outliers relate to traits such as body weight or size, metabolism, immunity, fat, eye function, and the cardiovascular system. We then compared these results with the results of analyses of published data from two transects in North America. While most candidate genes were unique to individual transects, we found significant overlap among candidate genes identified independently in the three transects. These genes are diverse, with functions relating to metabolism, immunity, cardiac function, and circadian rhythm, among others. We also found parallel shifts in allele frequency in candidate genes across latitudinal gradients. Finally, combining data from all three transects, we identified several genes associated with variation in body weight. Overall, our results provide strong evidence of shared responses to selection and identify genes that likely underlie recent environmental adaptation in house mice across North and South America.
Collapse
Affiliation(s)
- Yocelyn T. Gutiérrez-Guerrero
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
| | - Megan Phifer-Rixey
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Michael W. Nachman
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
| |
Collapse
|
8
|
Mikula LC, Vogl C. The expected sample allele frequencies from populations of changing size via orthogonal polynomials. Theor Popul Biol 2024; 157:55-85. [PMID: 38552964 DOI: 10.1016/j.tpb.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 03/24/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024]
Abstract
In this article, discrete and stochastic changes in (effective) population size are incorporated into the spectral representation of a biallelic diffusion process for drift and small mutation rates. A forward algorithm inspired by Hidden-Markov-Model (HMM) literature is used to compute exact sample allele frequency spectra for three demographic scenarios: single changes in (effective) population size, boom-bust dynamics, and stochastic fluctuations in (effective) population size. An approach for fully agnostic demographic inference from these sample allele spectra is explored, and sufficient statistics for stepwise changes in population size are found. Further, convergence behaviours of the polymorphic sample spectra for population size changes on different time scales are examined and discussed within the context of inference of the effective population size. Joint visual assessment of the sample spectra and the temporal coefficients of the spectral decomposition of the forward diffusion process is found to be important in determining departure from equilibrium. Stochastic changes in (effective) population size are shown to shape sample spectra particularly strongly.
Collapse
Affiliation(s)
- Lynette Caitlin Mikula
- Centre for Biological Diversity, School of Biology, University of St. Andrews, St, Andrews KY16 9TH, UK.
| | - Claus Vogl
- Department of Biomedical Sciences and Pathobiology, Vetmeduni Vienna, Veterinärplatz 1, A-1210 Wien, Austria; Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Veterinärplatz 1, A-1210 Wien, Austria.
| |
Collapse
|
9
|
Brud E. Season-specific dominance broadly stabilizes polymorphism under symmetric and asymmetric multivoltinism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.20.567918. [PMID: 38045349 PMCID: PMC10690222 DOI: 10.1101/2023.11.20.567918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Seasonality causes intraannual fitness changes in multivoltine populations (defined as having multiple generations per year). While it is well-known that seasonally balanced polymorphism is established by overdominance in geometric mean fitness, an unsettled aspect of the deterministic theory is the relative contribution of various season-specific dominance mechanisms to the potential for polymorphism. In particular, the relative importance of seasonally-reversing and non-reversing schemes remains unclear. Here I analyze the parameter space for the discrete generation two-season multivoltine model and conclude that, in general, a substantial fraction of stabilizing schemes are non-reversing with the season (~25-50%). In addition, I derive the approximate equilibrium allele frequency cycle under bivoltinism, and find that the amplitude of allelic oscillation is maximized by non-reversing dominance if the selection coefficients are roughly symmetric. Lastly, I derive conditions for the intralocus evolution of dominance. These predict a long-term trend toward maximally beneficial reversal. Overall, the results counter the disproportionate emphasis placed on dominance reversal as a stabilizing mechanism and clarify that non-reversing dominance is expected to frequently characterize seasonally fluctuating alleles under both weak and strong selection, especially in their early history. I conclude that seasonally alternating selection regimes are easily able to maintain allelic variation without restrictive assumptions on either selection coefficients or dominance parameters.
Collapse
Affiliation(s)
- Evgeny Brud
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
10
|
Williams-Simon PA, Oster C, Moaton JA, Ghidey R, Ng’oma E, Middleton KM, King EG. Naturally segregating genetic variants contribute to thermal tolerance in a Drosophila melanogaster model system. Genetics 2024; 227:iyae040. [PMID: 38506092 PMCID: PMC11075556 DOI: 10.1093/genetics/iyae040] [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: 07/11/2023] [Revised: 07/11/2023] [Accepted: 02/26/2024] [Indexed: 03/21/2024] Open
Abstract
Thermal tolerance is a fundamental physiological complex trait for survival in many species. For example, everyday tasks such as foraging, finding a mate, and avoiding predation are highly dependent on how well an organism can tolerate extreme temperatures. Understanding the general architecture of the natural variants within the genes that control this trait is of high importance if we want to better comprehend thermal physiology. Here, we take a multipronged approach to further dissect the genetic architecture that controls thermal tolerance in natural populations using the Drosophila Synthetic Population Resource as a model system. First, we used quantitative genetics and Quantitative Trait Loci mapping to identify major effect regions within the genome that influences thermal tolerance, then integrated RNA-sequencing to identify differences in gene expression, and lastly, we used the RNAi system to (1) alter tissue-specific gene expression and (2) functionally validate our findings. This powerful integration of approaches not only allows for the identification of the genetic basis of thermal tolerance but also the physiology of thermal tolerance in a natural population, which ultimately elucidates thermal tolerance through a fitness-associated lens.
Collapse
Affiliation(s)
- Patricka A Williams-Simon
- Department of Biology, University of Pennsylvania, 433 S University Ave., 226 Leidy Laboratories, Philadelphia, PA 19104, USA
| | - Camille Oster
- Ash Creek Forest Management, 2796 SE 73rd Ave., Hillsboro, OR 97123, USA
| | | | - Ronel Ghidey
- ECHO Data Analysis Center, Johns Hopkins Bloomberg School of Public Health, 504 Cathedral St., Baltimore, MD 2120, USA
| | - Enoch Ng’oma
- Division of Biology, University of Missouri, 226 Tucker Hall, Columbia, MO 65211, USA
| | - Kevin M Middleton
- Division of Biology, University of Missouri, 222 Tucker Hall, Columbia, MO 65211, USA
| | - Elizabeth G King
- Division of Biology, University of Missouri, 401 Tucker Hall, Columbia, MO 65211, USA
| |
Collapse
|
11
|
Glaser-Schmitt A, Ramnarine TJS, Parsch J. Rapid evolutionary change, constraints and the maintenance of polymorphism in natural populations of Drosophila melanogaster. Mol Ecol 2024; 33:e17024. [PMID: 37222070 DOI: 10.1111/mec.17024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 04/28/2023] [Accepted: 05/05/2023] [Indexed: 05/25/2023]
Abstract
Allele frequencies can shift rapidly within natural populations. Under certain conditions, repeated rapid allele frequency shifts can lead to the long-term maintenance of polymorphism. In recent years, studies of the model insect Drosophila melanogaster have suggested that this phenomenon is more common than previously believed and is often driven by some form of balancing selection, such as temporally fluctuating or sexually antagonistic selection. Here we discuss some of the general insights into rapid evolutionary change revealed by large-scale population genomic studies, as well as the functional and mechanistic causes of rapid adaptation uncovered by single-gene studies. As an example of the latter, we consider a regulatory polymorphism of the D. melanogaster fezzik gene. Polymorphism at this site has been maintained at intermediate frequency over an extended period of time. Regular observations from a single population over a period of 7 years revealed significant differences in the frequency of the derived allele and its variance across collections between the sexes. These patterns are highly unlikely to arise from genetic drift alone or from the action of sexually antagonistic or temporally fluctuating selection individually. Instead, the joint action of sexually antagonistic and temporally fluctuating selection can best explain the observed rapid and repeated allele frequency shifts. Temporal studies such as those reviewed here further our understanding of how rapid changes in selection can lead to the long-term maintenance of polymorphism as well as improve our knowledge of the forces driving and limiting adaptation in nature.
Collapse
Affiliation(s)
- Amanda Glaser-Schmitt
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Timothy J S Ramnarine
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - John Parsch
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| |
Collapse
|
12
|
Chen J, Liu C, Li W, Zhang W, Wang Y, Clark AG, Lu J. From sub-Saharan Africa to China: Evolutionary history and adaptation of Drosophila melanogaster revealed by population genomics. SCIENCE ADVANCES 2024; 10:eadh3425. [PMID: 38630810 PMCID: PMC11023512 DOI: 10.1126/sciadv.adh3425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 03/13/2024] [Indexed: 04/19/2024]
Abstract
Drosophila melanogaster is a widely used model organism for studying environmental adaptation. However, the genetic diversity of populations in Asia is poorly understood, leaving a notable gap in our knowledge of the global evolution and adaptation of this species. We sequenced genomes of 292 D. melanogaster strains from various ecological settings in China and analyzed them along with previously published genome sequences. We have identified six global genetic ancestry groups, despite the presence of widespread genetic admixture. The strains from China represent a unique ancestry group, although detectable differentiation exists among populations within China. We deciphered the global migration and demography of D. melanogaster, and identified widespread signals of adaptation, including genetic changes in response to insecticides. We validated the effects of insecticide resistance variants using population cage trials and deep sequencing. This work highlights the importance of population genomics in understanding the genetic underpinnings of adaptation, an effort that is particularly relevant given the deterioration of ecosystems.
Collapse
Affiliation(s)
- Junhao Chen
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China
| | - Chenlu Liu
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China
| | - Weixuan Li
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China
| | - Wenxia Zhang
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yirong Wang
- College of Biology, Hunan University, Changsha 410082, China
| | - Andrew G. Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jian Lu
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing 100871, China
| |
Collapse
|
13
|
Johnson OL, Tobler R, Schmidt JM, Huber CD. Population genetic simulation: Benchmarking frameworks for non-standard models of natural selection. Mol Ecol Resour 2024; 24:e13930. [PMID: 38247258 DOI: 10.1111/1755-0998.13930] [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: 10/17/2023] [Revised: 12/21/2023] [Accepted: 01/09/2024] [Indexed: 01/23/2024]
Abstract
Population genetic simulation has emerged as a common tool for investigating increasingly complex evolutionary and demographic models. Software capable of handling high-level model complexity has recently been developed, and the advancement of tree sequence recording now allows simulations to merge the efficiency and genealogical insight of coalescent simulations with the flexibility of forward simulations. However, frameworks utilizing these features have not yet been compared and benchmarked. Here, we evaluate various simulation workflows using the coalescent simulator msprime and the forward simulator SLiM, to assess resource efficiency and determine an optimal simulation framework. Three aspects were evaluated: (1) the burn-in, to establish an equilibrium level of neutral diversity in the population; (2) the forward simulation, in which temporally fluctuating selection is acting; and (3) the final computation of summary statistics. We provide typical memory and computation time requirements for each step. We find that the fastest framework, a combination of coalescent and forward simulation with tree sequence recording, increases simulation speed by over twenty times compared to classical forward simulations without tree sequence recording, although it does require six times more memory. Overall, using efficient simulation workflows can lead to a substantial improvement when modelling complex evolutionary scenarios-although the optimal framework ultimately depends on the available computational resources.
Collapse
Affiliation(s)
- Olivia L Johnson
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Raymond Tobler
- Evolution of Cultural Diversity Initiative, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Joshua M Schmidt
- Department of Ophthalmology, College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Christian D Huber
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| |
Collapse
|
14
|
Grieshop K, Ho EKH, Kasimatis KR. Dominance reversals: the resolution of genetic conflict and maintenance of genetic variation. Proc Biol Sci 2024; 291:20232816. [PMID: 38471544 DOI: 10.1098/rspb.2023.2816] [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: 06/02/2023] [Accepted: 02/05/2024] [Indexed: 03/14/2024] Open
Abstract
Beneficial reversals of dominance reduce the costs of genetic trade-offs and can enable selection to maintain genetic variation for fitness. Beneficial dominance reversals are characterized by the beneficial allele for a given context (e.g. habitat, developmental stage, trait or sex) being dominant in that context but recessive where deleterious. This context dependence at least partially mitigates the fitness consequence of heterozygotes carrying one non-beneficial allele for their context and can result in balancing selection that maintains alternative alleles. Dominance reversals are theoretically plausible and are supported by mounting empirical evidence. Here, we highlight the importance of beneficial dominance reversals as a mechanism for the mitigation of genetic conflict and review the theory and empirical evidence for them. We identify some areas in need of further research and development and outline three methods that could facilitate the identification of antagonistic genetic variation (dominance ordination, allele-specific expression and allele-specific ATAC-Seq (assay for transposase-accessible chromatin with sequencing)). There is ample scope for the development of new empirical methods as well as reanalysis of existing data through the lens of dominance reversals. A greater focus on this topic will expand our understanding of the mechanisms that resolve genetic conflict and whether they maintain genetic variation.
Collapse
Affiliation(s)
- Karl Grieshop
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada M5S 1A1
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Eddie K H Ho
- Department of Biology, Reed College, 3203 SE Woodstock Blvd, Portland, OR 97202, USA
| | - Katja R Kasimatis
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada M5S 1A1
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| |
Collapse
|
15
|
Pianezza R, Scarpa A, Narayanan P, Signor S, Kofler R. Spoink, a LTR retrotransposon, invaded D. melanogaster populations in the 1990s. PLoS Genet 2024; 20:e1011201. [PMID: 38530818 DOI: 10.1371/journal.pgen.1011201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
During the last few centuries D. melanogaster populations were invaded by several transposable elements, the most recent of which was thought to be the P-element between 1950 and 1980. Here we describe a novel TE, which we named Spoink, that has invaded D. melanogaster. It is a 5216nt LTR retrotransposon of the Ty3/gypsy superfamily. Relying on strains sampled at different times during the last century we show that Spoink invaded worldwide D. melanogaster populations after the P-element between 1983 and 1993. This invasion was likely triggered by a horizontal transfer from the D. willistoni group, much as the P-element. Spoink is probably silenced by the piRNA pathway in natural populations and about 1/3 of the examined strains have an insertion into a canonical piRNA cluster such as 42AB. Given the degree of genetic investigation of D. melanogaster it is perhaps surprising that Spoink was able to invade unnoticed.
Collapse
Affiliation(s)
- Riccardo Pianezza
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Almorò Scarpa
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Prakash Narayanan
- Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Sarah Signor
- Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Robert Kofler
- Institut für Populationsgenetik, Vetmeduni Vienna, Vienna, Austria
| |
Collapse
|
16
|
Bernatchez L, Ferchaud AL, Berger CS, Venney CJ, Xuereb A. Genomics for monitoring and understanding species responses to global climate change. Nat Rev Genet 2024; 25:165-183. [PMID: 37863940 DOI: 10.1038/s41576-023-00657-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2023] [Indexed: 10/22/2023]
Abstract
All life forms across the globe are experiencing drastic changes in environmental conditions as a result of global climate change. These environmental changes are happening rapidly, incur substantial socioeconomic costs, pose threats to biodiversity and diminish a species' potential to adapt to future environments. Understanding and monitoring how organisms respond to human-driven climate change is therefore a major priority for the conservation of biodiversity in a rapidly changing environment. Recent developments in genomic, transcriptomic and epigenomic technologies are enabling unprecedented insights into the evolutionary processes and molecular bases of adaptation. This Review summarizes methods that apply and integrate omics tools to experimentally investigate, monitor and predict how species and communities in the wild cope with global climate change, which is by genetically adapting to new environmental conditions, through range shifts or through phenotypic plasticity. We identify advantages and limitations of each method and discuss future research avenues that would improve our understanding of species' evolutionary responses to global climate change, highlighting the need for holistic, multi-omics approaches to ecosystem monitoring during global climate change.
Collapse
Affiliation(s)
- Louis Bernatchez
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
| | - Anne-Laure Ferchaud
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada.
- Parks Canada, Office of the Chief Ecosystem Scientist, Protected Areas Establishment, Quebec City, Quebec, Canada.
| | - Chloé Suzanne Berger
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
| | - Clare J Venney
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
| | - Amanda Xuereb
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec City, Quebec, Canada
| |
Collapse
|
17
|
Lafuente E, Duneau D, Beldade P. Genetic basis of variation in thermal developmental plasticity for Drosophila melanogaster body pigmentation. Mol Ecol 2024; 33:e17294. [PMID: 38366327 DOI: 10.1111/mec.17294] [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: 09/13/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/18/2024]
Abstract
Seasonal differences in insect pigmentation are attributed to the influence of ambient temperature on pigmentation development. This thermal plasticity is adaptive and heritable, and thereby capable of evolving. However, the specific genes contributing to the variation in plasticity that can drive its evolution remain largely unknown. To address this, we analysed pigmentation and pigmentation plasticity in Drosophila melanogaster. We measured two components of pigmentation in the thorax and abdomen: overall darkness and the proportion of length covered by darker pattern elements (a trident in the thorax and bands in the abdomen) in females from two developmental temperatures (17 or 28°C) and 191 genotypes. Using a GWAS approach to identify the genetic basis of variation in pigmentation and its response to temperature, we identified numerous dispersed QTLs, including some mapping to melanogenesis genes (yellow, ebony, and tan). Remarkably, we observed limited overlap between QTLs for variation within specific temperatures and those influencing thermal plasticity, as well as minimal overlap between plasticity QTLs across pigmentation components and across body parts. For most traits, consistent with selection favouring the retention of plasticity, we found that lower plasticity alleles were often at lower frequencies. The functional analysis of selected candidate QTLs and pigmentation genes largely confirmed their contributions to variation in pigmentation and/or pigmentation plasticity. Overall, our study reveals the existence and underlying basis of extensive and trait-specific genetic variation for pigmentation and pigmentation plasticity, offering a rich reservoir of raw material for natural selection to shape the evolution of these traits independently.
Collapse
Affiliation(s)
- E Lafuente
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - D Duneau
- UMR5174, Laboratoire Évolution & Diversité Biologique, Université Paul Sabatier, Toulouse, France
- Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - P Beldade
- cE3c (Center for Ecology, Evolution and Environmental Changes) & CHANGE (Global Change and Sustainability Institute), FCUL, Lisboa, Portugal
| |
Collapse
|
18
|
Bitter MC, Berardi S, Oken H, Huynh A, Schmidt P, Petrov DA. Continuously fluctuating selection reveals extreme granularity and parallelism of adaptive tracking. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.16.562586. [PMID: 37904939 PMCID: PMC10614893 DOI: 10.1101/2023.10.16.562586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Temporally fluctuating environmental conditions are a ubiquitous feature of natural habitats. Yet, how finely natural populations adaptively track fluctuating selection pressures via shifts in standing genetic variation is unknown. We generated high-frequency, genome-wide allele frequency data from a genetically diverse population of Drosophila melanogaster in extensively replicated field mesocosms from late June to mid-December, a period of ∼12 generations. Adaptation throughout the fundamental ecological phases of population expansion, peak density, and collapse was underpinned by extremely rapid, parallel changes in genomic variation across replicates. Yet, the dominant direction of selection fluctuated repeatedly, even within each of these ecological phases. Comparing patterns of allele frequency change to an independent dataset procured from the same experimental system demonstrated that the targets of selection are predictable across years. In concert, our results reveal fitness-relevance of standing variation that is likely to be masked by inference approaches based on static population sampling, or insufficiently resolved time-series data. We propose such fine-scaled temporally fluctuating selection may be an important force maintaining functional genetic variation in natural populations and an important stochastic force affecting levels of standing genetic variation genome-wide.
Collapse
|
19
|
Simon A, Coop G. The contribution of gene flow, selection, and genetic drift to five thousand years of human allele frequency change. Proc Natl Acad Sci U S A 2024; 121:e2312377121. [PMID: 38363870 PMCID: PMC10907250 DOI: 10.1073/pnas.2312377121] [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: 07/19/2023] [Accepted: 01/09/2024] [Indexed: 02/18/2024] Open
Abstract
Genomic time series from experimental evolution studies and ancient DNA datasets offer us a chance to directly observe the interplay of various evolutionary forces. We show how the genome-wide variance in allele frequency change between two time points can be decomposed into the contributions of gene flow, genetic drift, and linked selection. In closed populations, the contribution of linked selection is identifiable because it creates covariances between time intervals, and genetic drift does not. However, repeated gene flow between populations can also produce directionality in allele frequency change, creating covariances. We show how to accurately separate the fraction of variance in allele frequency change due to admixture and linked selection in a population receiving gene flow. We use two human ancient DNA datasets, spanning around 5,000 y, as time transects to quantify the contributions to the genome-wide variance in allele frequency change. We find that a large fraction of genome-wide change is due to gene flow. In both cases, after correcting for known major gene flow events, we do not observe a signal of genome-wide linked selection. Thus despite the known role of selection in shaping long-term polymorphism levels, and an increasing number of examples of strong selection on single loci and polygenic scores from ancient DNA, it appears to be gene flow and drift, and not selection, that are the main determinants of recent genome-wide allele frequency change. Our approach should be applicable to the growing number of contemporary and ancient temporal population genomics datasets.
Collapse
Affiliation(s)
- Alexis Simon
- Center for Population Biology, University of California, Davis, CA95616
- Department of Evolution and Ecology, University of California, Davis, CA95616
| | - Graham Coop
- Center for Population Biology, University of California, Davis, CA95616
- Department of Evolution and Ecology, University of California, Davis, CA95616
| |
Collapse
|
20
|
Nunez JCB, Lenhart BA, Bangerter A, Murray CS, Mazzeo GR, Yu Y, Nystrom TL, Tern C, Erickson PA, Bergland AO. A cosmopolitan inversion facilitates seasonal adaptation in overwintering Drosophila. Genetics 2024; 226:iyad207. [PMID: 38051996 PMCID: PMC10847723 DOI: 10.1093/genetics/iyad207] [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: 10/08/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023] Open
Abstract
Fluctuations in the strength and direction of natural selection through time are a ubiquitous feature of life on Earth. One evolutionary outcome of such fluctuations is adaptive tracking, wherein populations rapidly adapt from standing genetic variation. In certain circumstances, adaptive tracking can lead to the long-term maintenance of functional polymorphism despite allele frequency change due to selection. Although adaptive tracking is likely a common process, we still have a limited understanding of aspects of its genetic architecture and its strength relative to other evolutionary forces such as drift. Drosophila melanogaster living in temperate regions evolve to track seasonal fluctuations and are an excellent system to tackle these gaps in knowledge. By sequencing orchard populations collected across multiple years, we characterized the genomic signal of seasonal demography and identified that the cosmopolitan inversion In(2L)t facilitates seasonal adaptive tracking and shows molecular footprints of selection. A meta-analysis of phenotypic studies shows that seasonal loci within In(2L)t are associated with behavior, life history, physiology, and morphological traits. We identify candidate loci and experimentally link them to phenotype. Our work contributes to our general understanding of fluctuating selection and highlights the evolutionary outcome and dynamics of contemporary selection on inversions.
Collapse
Affiliation(s)
- Joaquin C B Nunez
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
- Department of Biology, University of Vermont, 109 Carrigan Drive, Burlington, VT 05405, USA
| | - Benedict A Lenhart
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Alyssa Bangerter
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Connor S Murray
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Giovanni R Mazzeo
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Yang Yu
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Taylor L Nystrom
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Courtney Tern
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Priscilla A Erickson
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
- Department of Biology, University of Richmond, 138 UR Drive, Richmond, VA 23173, USA
| | - Alan O Bergland
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| |
Collapse
|
21
|
Song S, Zhang J. Effective fitness under fluctuating selection with genetic drift. G3 (BETHESDA, MD.) 2023; 13:jkad230. [PMID: 37816122 PMCID: PMC10700052 DOI: 10.1093/g3journal/jkad230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/29/2023] [Accepted: 09/28/2023] [Indexed: 10/12/2023]
Abstract
The natural environment fluctuates for virtually every population of organisms. As a result, the fitness of a mutant may vary temporally. While commonly used for summarizing the effect of fluctuating selection on the mutant, geometric mean fitness can be misleading under some circumstances due to the influence of genetic drift. Here, we show by mathematical proof and computer simulation that, with genetic drift, the geometric mean fitness does not accurately reflect the overall effect of fluctuating selection. We propose an alternative measure based on the average expected allele frequency change caused by selection and demonstrate that this measure-effective fitness-better captures the overall effect of fluctuating selection in the presence of drift.
Collapse
Affiliation(s)
- Siliang Song
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
22
|
Berdan EL, Barton NH, Butlin R, Charlesworth B, Faria R, Fragata I, Gilbert KJ, Jay P, Kapun M, Lotterhos KE, Mérot C, Durmaz Mitchell E, Pascual M, Peichel CL, Rafajlović M, Westram AM, Schaeffer SW, Johannesson K, Flatt T. How chromosomal inversions reorient the evolutionary process. J Evol Biol 2023; 36:1761-1782. [PMID: 37942504 DOI: 10.1111/jeb.14242] [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: 05/05/2023] [Revised: 09/13/2023] [Accepted: 10/05/2023] [Indexed: 11/10/2023]
Abstract
Inversions are structural mutations that reverse the sequence of a chromosome segment and reduce the effective rate of recombination in the heterozygous state. They play a major role in adaptation, as well as in other evolutionary processes such as speciation. Although inversions have been studied since the 1920s, they remain difficult to investigate because the reduced recombination conferred by them strengthens the effects of drift and hitchhiking, which in turn can obscure signatures of selection. Nonetheless, numerous inversions have been found to be under selection. Given recent advances in population genetic theory and empirical study, here we review how different mechanisms of selection affect the evolution of inversions. A key difference between inversions and other mutations, such as single nucleotide variants, is that the fitness of an inversion may be affected by a larger number of frequently interacting processes. This considerably complicates the analysis of the causes underlying the evolution of inversions. We discuss the extent to which these mechanisms can be disentangled, and by which approach.
Collapse
Affiliation(s)
- Emma L Berdan
- Bioinformatics Core, Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Nicholas H Barton
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Roger Butlin
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- Ecology and Evolutionary Biology, School of Bioscience, The University of Sheffield, Sheffield, UK
| | - Brian Charlesworth
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Rui Faria
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Inês Fragata
- CHANGE - Global Change and Sustainability Institute/Animal Biology Department, cE3c - Center for Ecology, Evolution and Environmental Changes, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | | | - Paul Jay
- Center for GeoGenetics, University of Copenhagen, Copenhagen, Denmark
| | - Martin Kapun
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
- Central Research Laboratories, Natural History Museum of Vienna, Vienna, Austria
| | - Katie E Lotterhos
- Department of Marine and Environmental Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Claire Mérot
- UMR 6553 Ecobio, Université de Rennes, OSUR, CNRS, Rennes, France
| | - Esra Durmaz Mitchell
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Functional Genomics & Metabolism Research Unit, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Marta Pascual
- Departament de Genètica, Microbiologia i Estadística, Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | - Catherine L Peichel
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Marina Rafajlović
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - Anja M Westram
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Stephen W Schaeffer
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kerstin Johannesson
- Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| |
Collapse
|
23
|
Shpak M, Ghanavi HR, Lange JD, Pool JE, Stensmyr MC. Genomes from historical Drosophila melanogaster specimens illuminate adaptive and demographic changes across more than 200 years of evolution. PLoS Biol 2023; 21:e3002333. [PMID: 37824452 PMCID: PMC10569592 DOI: 10.1371/journal.pbio.3002333] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 09/11/2023] [Indexed: 10/14/2023] Open
Abstract
The ability to perform genomic sequencing on long-dead organisms is opening new frontiers in evolutionary research. These opportunities are especially notable in the case of museum collections, from which countless documented specimens may now be suitable for genomic analysis-if data of sufficient quality can be obtained. Here, we report 25 newly sequenced genomes from museum specimens of the model organism Drosophila melanogaster, including the oldest extant specimens of this species. By comparing historical samples ranging from the early 1800s to 1933 against modern-day genomes, we document evolution across thousands of generations, including time periods that encompass the species' initial occupation of northern Europe and an era of rapidly increasing human activity. We also find that the Lund, Sweden population underwent local genetic differentiation during the early 1800s to 1933 interval (potentially due to drift in a small population) but then became more similar to other European populations thereafter (potentially due to increased migration). Within each century-scale time period, our temporal sampling allows us to document compelling candidates for recent natural selection. In some cases, we gain insights regarding previously implicated selection candidates, such as ChKov1, for which our inferred timing of selection favors the hypothesis of antiviral resistance over insecticide resistance. Other candidates are novel, such as the circadian-related gene Ahcy, which yields a selection signal that rivals that of the DDT resistance gene Cyp6g1. These insights deepen our understanding of recent evolution in a model system, and highlight the potential of future museomic studies.
Collapse
Affiliation(s)
- Max Shpak
- Laboratory of Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | | | - Jeremy D. Lange
- Laboratory of Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - John E. Pool
- Laboratory of Genetics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Marcus C. Stensmyr
- Department of Biology, Lund University, Lund, Scania, Sweden
- Max Planck Center on Next Generation Insect Chemical Ecology, Lund, Sweden
| |
Collapse
|
24
|
Arnqvist G, Rowe L. Ecology, the pace-of-life, epistatic selection and the maintenance of genetic variation in life-history genes. Mol Ecol 2023; 32:4713-4724. [PMID: 37386734 DOI: 10.1111/mec.17062] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 06/09/2023] [Accepted: 06/19/2023] [Indexed: 07/01/2023]
Abstract
Evolutionary genetics has long struggled with understanding how functional genes under selection remain polymorphic in natural populations. Taking as a starting point that natural selection is ultimately a manifestation of ecological processes, we spotlight an underemphasized and potentially ubiquitous ecological effect that may have fundamental effects on the maintenance of genetic variation. Negative frequency dependency is a well-established emergent property of density dependence in ecology, because the relative profitability of different modes of exploiting or utilizing limiting resources tends to be inversely proportional to their frequency in a population. We suggest that this may often generate negative frequency-dependent selection (NFDS) on major effect loci that affect rate-dependent physiological processes, such as metabolic rate, that are phenotypically manifested as polymorphism in pace-of-life syndromes. When such a locus under NFDS shows stable intermediate frequency polymorphism, this should generate epistatic selection potentially involving large numbers of loci with more minor effects on life-history (LH) traits. When alternative alleles at such loci show sign epistasis with a major effect locus, this associative NFDS will promote the maintenance of polygenic variation in LH genes. We provide examples of the kind of major effect loci that could be involved and suggest empirical avenues that may better inform us on the importance and reach of this process.
Collapse
Affiliation(s)
- Göran Arnqvist
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Locke Rowe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- Swedish Collegium of Advanced Study, Uppsala, Sweden
| |
Collapse
|
25
|
Yamamichi M, Letten AD, Schreiber SJ. Eco-evolutionary maintenance of diversity in fluctuating environments. Ecol Lett 2023; 26 Suppl 1:S152-S167. [PMID: 37840028 DOI: 10.1111/ele.14286] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 06/23/2023] [Accepted: 06/24/2023] [Indexed: 10/17/2023]
Abstract
Growing evidence suggests that temporally fluctuating environments are important in maintaining variation both within and between species. To date, however, studies of genetic variation within a population have been largely conducted by evolutionary biologists (particularly population geneticists), while population and community ecologists have concentrated more on diversity at the species level. Despite considerable conceptual overlap, the commonalities and differences of these two alternative paradigms have yet to come under close scrutiny. Here, we review theoretical and empirical studies in population genetics and community ecology focusing on the 'temporal storage effect' and synthesise theories of diversity maintenance across different levels of biological organisation. Drawing on Chesson's coexistence theory, we explain how temporally fluctuating environments promote the maintenance of genetic variation and species diversity. We propose a further synthesis of the two disciplines by comparing models employing traditional frequency-dependent dynamics and those adopting density-dependent dynamics. We then address how temporal fluctuations promote genetic and species diversity simultaneously via rapid evolution and eco-evolutionary dynamics. Comparing and synthesising ecological and evolutionary approaches will accelerate our understanding of diversity maintenance in nature.
Collapse
Affiliation(s)
- Masato Yamamichi
- School of Biological Sciences, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
- Department of International Health and Medical Anthropology, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Andrew D Letten
- School of Biological Sciences, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Sebastian J Schreiber
- Department of Evolution and Ecology and Center for Population Biology, University of California, Davis, California, USA
| |
Collapse
|
26
|
Williams-Simon PA, Oster C, Moaton JA, Ghidey R, Ng'oma E, Middleton KM, Zars T, King EG. Naturally segregating genetic variants contribute to thermal tolerance in a D. melanogaster model system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.06.547110. [PMID: 37461510 PMCID: PMC10350013 DOI: 10.1101/2023.07.06.547110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Thermal tolerance is a fundamental physiological complex trait for survival in many species. For example, everyday tasks such as foraging, finding a mate, and avoiding predation, are highly dependent on how well an organism can tolerate extreme temperatures. Understanding the general architecture of the natural variants of the genes that control this trait is of high importance if we want to better comprehend how this trait evolves in natural populations. Here, we take a multipronged approach to further dissect the genetic architecture that controls thermal tolerance in natural populations using the Drosophila Synthetic Population Resource (DSPR) as a model system. First, we used quantitative genetics and Quantitative Trait Loci (QTL) mapping to identify major effect regions within the genome that influences thermal tolerance, then integrated RNA-sequencing to identify differences in gene expression, and lastly, we used the RNAi system to 1) alter tissue-specific gene expression and 2) functionally validate our findings. This powerful integration of approaches not only allows for the identification of the genetic basis of thermal tolerance but also the physiology of thermal tolerance in a natural population, which ultimately elucidates thermal tolerance through a fitness-associated lens.
Collapse
|
27
|
Whitehouse LS, Schrider DR. Timesweeper: accurately identifying selective sweeps using population genomic time series. Genetics 2023; 224:iyad084. [PMID: 37157914 PMCID: PMC10324941 DOI: 10.1093/genetics/iyad084] [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: 07/25/2022] [Revised: 07/25/2022] [Accepted: 04/25/2023] [Indexed: 05/10/2023] Open
Abstract
Despite decades of research, identifying selective sweeps, the genomic footprints of positive selection, remains a core problem in population genetics. Of the myriad methods that have been developed to tackle this task, few are designed to leverage the potential of genomic time-series data. This is because in most population genetic studies of natural populations, only a single period of time can be sampled. Recent advancements in sequencing technology, including improvements in extracting and sequencing ancient DNA, have made repeated samplings of a population possible, allowing for more direct analysis of recent evolutionary dynamics. Serial sampling of organisms with shorter generation times has also become more feasible due to improvements in the cost and throughput of sequencing. With these advances in mind, here we present Timesweeper, a fast and accurate convolutional neural network-based tool for identifying selective sweeps in data consisting of multiple genomic samplings of a population over time. Timesweeper analyzes population genomic time-series data by first simulating training data under a demographic model appropriate for the data of interest, training a one-dimensional convolutional neural network on said simulations, and inferring which polymorphisms in this serialized data set were the direct target of a completed or ongoing selective sweep. We show that Timesweeper is accurate under multiple simulated demographic and sampling scenarios, identifies selected variants with high resolution, and estimates selection coefficients more accurately than existing methods. In sum, we show that more accurate inferences about natural selection are possible when genomic time-series data are available; such data will continue to proliferate in coming years due to both the sequencing of ancient samples and repeated samplings of extant populations with faster generation times, as well as experimentally evolved populations where time-series data are often generated. Methodological advances such as Timesweeper thus have the potential to help resolve the controversy over the role of positive selection in the genome. We provide Timesweeper as a Python package for use by the community.
Collapse
Affiliation(s)
- Logan S Whitehouse
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27514, USA
| | - Daniel R Schrider
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27514, USA
| |
Collapse
|
28
|
Kim Y. Partial protection from fluctuating selection leads to evolution towards wider population size fluctuation and a novel mechanism of balancing selection. Proc Biol Sci 2023; 290:20230822. [PMID: 37339748 DOI: 10.1098/rspb.2023.0822] [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: 12/20/2022] [Accepted: 05/26/2023] [Indexed: 06/22/2023] Open
Abstract
When a population is partially protected from fluctuating selection, as when a seed bank is present, variance in fitness will be reduced and reproductive success of the population will be promoted. This study further investigates the effect of such a 'refuge' from fluctuating selection using a mathematical model that couples demographic and evolutionary dynamics. While alleles that cause smaller fluctuations in population density should be positively selected according to classical theoretic predictions, this study finds the opposite: alleles that increase the amplitude of population size fluctuation are positively selected if population density is weakly regulated. Under strong density regulation with a constant carrying capacity, long-term maintenance of polymorphism caused by the storage effect emerges. However, if the carrying capacity of the population is oscillating, mutant alleles whose fitness fluctuates in the same direction as population size are positively selected, eventually reaching fixation or intermediate frequencies that oscillate over time. This oscillatory polymorphism, which requires fitness fluctuations that can arise with simple trade-offs in life-history traits, is a novel form of balancing selection. These results highlight the importance of allowing joint demographic and population genetic changes in models, the failure of which prevents the discovery of novel eco-evolutionary dynamics.
Collapse
Affiliation(s)
- Yuseob Kim
- Division of EcoScience and Department of Life Science, Ewha Womans University, Ewhayeodae-gil 52, Seodaemun-gu, Seoul 03760, Korea
| |
Collapse
|
29
|
von Schmalensee L, Caillault P, Gunnarsdóttir KH, Gotthard K, Lehmann P. Seasonal specialization drives divergent population dynamics in two closely related butterflies. Nat Commun 2023; 14:3663. [PMID: 37339960 DOI: 10.1038/s41467-023-39359-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 06/07/2023] [Indexed: 06/22/2023] Open
Abstract
Seasons impose different selection pressures on organisms through contrasting environmental conditions. How such seasonal evolutionary conflict is resolved in organisms whose lives span across seasons remains underexplored. Through field experiments, laboratory work, and citizen science data analyses, we investigate this question using two closely related butterflies (Pieris rapae and P. napi). Superficially, the two butterflies appear highly ecologically similar. Yet, the citizen science data reveal that their fitness is partitioned differently across seasons. Pieris rapae have higher population growth during the summer season but lower overwintering success than do P. napi. We show that these differences correspond to the physiology and behavior of the butterflies. Pieris rapae outperform P. napi at high temperatures in several growth season traits, reflected in microclimate choice by ovipositing wild females. Instead, P. rapae have higher winter mortality than do P. napi. We conclude that the difference in population dynamics between the two butterflies is driven by seasonal specialization, manifested as strategies that maximize gains during growth seasons and minimize harm during adverse seasons, respectively.
Collapse
Affiliation(s)
- Loke von Schmalensee
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden.
- Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Pauline Caillault
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden
| | | | - Karl Gotthard
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Philipp Lehmann
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden
- Department of Animal Physiology, Zoological Institute and Museum, University of Greifswald, 1D-17489, Greifswald, Germany
| |
Collapse
|
30
|
Kapun M, Mitchell ED, Kawecki TJ, Schmidt P, Flatt T. An Ancestral Balanced Inversion Polymorphism Confers Global Adaptation. Mol Biol Evol 2023; 40:msad118. [PMID: 37220650 PMCID: PMC10234209 DOI: 10.1093/molbev/msad118] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/17/2023] [Accepted: 05/19/2023] [Indexed: 05/25/2023] Open
Abstract
Since the pioneering work of Dobzhansky in the 1930s and 1940s, many chromosomal inversions have been identified, but how they contribute to adaptation remains poorly understood. In Drosophila melanogaster, the widespread inversion polymorphism In(3R)Payne underpins latitudinal clines in fitness traits on multiple continents. Here, we use single-individual whole-genome sequencing, transcriptomics, and published sequencing data to study the population genomics of this inversion on four continents: in its ancestral African range and in derived populations in Europe, North America, and Australia. Our results confirm that this inversion originated in sub-Saharan Africa and subsequently became cosmopolitan; we observe marked monophyletic divergence of inverted and noninverted karyotypes, with some substructure among inverted chromosomes between continents. Despite divergent evolution of this inversion since its out-of-Africa migration, derived non-African populations exhibit similar patterns of long-range linkage disequilibrium between the inversion breakpoints and major peaks of divergence in its center, consistent with balancing selection and suggesting that the inversion harbors alleles that are maintained by selection on several continents. Using RNA-sequencing, we identify overlap between inversion-linked single-nucleotide polymorphisms and loci that are differentially expressed between inverted and noninverted chromosomes. Expression levels are higher for inverted chromosomes at low temperature, suggesting loss of buffering or compensatory plasticity and consistent with higher inversion frequency in warm climates. Our results suggest that this ancestrally tropical balanced polymorphism spread around the world and became latitudinally assorted along similar but independent climatic gradients, always being frequent in subtropical/tropical areas but rare or absent in temperate climates.
Collapse
Affiliation(s)
- Martin Kapun
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Division of Cell and Developmental Biology, Medical University of Vienna, Vienna, Austria
- Natural History Museum Vienna, Zentrale Forschungslaboratorien, Vienna, Austria
| | - Esra Durmaz Mitchell
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Tadeusz J Kawecki
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Paul Schmidt
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Thomas Flatt
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| |
Collapse
|
31
|
Lynch M, Wei W, Ye Z, Pfrender M. The Genome-wide Signature of Short-term Temporal Selection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.28.538790. [PMID: 37162919 PMCID: PMC10168312 DOI: 10.1101/2023.04.28.538790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Despite evolutionary biology's obsession with natural selection, few studies have evaluated multi-generational series of patterns of selection on a genome-wide scale in natural populations. Here, we report on a nine-year population-genomic survey of the microcrustacean Daphnia pulex. The genome-sequences of > 800 isolates provide insights into patterns of selection that cannot be obtained from long-term molecular-evolution studies, including the pervasiveness of near quasi-neutrality across the genome (mean net selection coefficients near zero, but with significant temporal variance about the mean, and little evidence of positive covariance of selection across time intervals), the preponderance of weak negative selection operating on minor alleles, and a genome-wide distribution of numerous small linkage islands of observable selection influencing levels of nucleotide diversity. These results suggest that fluctuating selection is a major determinant of standing levels of variation in natural populations, challenge the conventional paradigm for interpreting patterns of nucleotide diversity and divergence, and motivate the need for the development of new theoretical expressions for the interpretation of population-genomic data.
Collapse
Affiliation(s)
- Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287
| | - Wen Wei
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287
| | - Zhiqiang Ye
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287
| | - Michael Pfrender
- Department of Biological Sciences, Notre Dame University, Notre Dame, IN 46556
| |
Collapse
|
32
|
Fluctuating selection and the determinants of genetic variation. Trends Genet 2023; 39:491-504. [PMID: 36890036 DOI: 10.1016/j.tig.2023.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 03/08/2023]
Abstract
Recent studies of cosmopolitan Drosophila populations have found hundreds to thousands of genetic loci with seasonally fluctuating allele frequencies, bringing temporally fluctuating selection to the forefront of the historical debate surrounding the maintenance of genetic variation in natural populations. Numerous mechanisms have been explored in this longstanding area of research, but these exciting empirical findings have prompted several recent theoretical and experimental studies that seek to better understand the drivers, dynamics, and genome-wide influence of fluctuating selection. In this review, we evaluate the latest evidence for multilocus fluctuating selection in Drosophila and other taxa, highlighting the role of potential genetic and ecological mechanisms in maintaining these loci and their impacts on neutral genetic variation.
Collapse
|
33
|
Chung MY, Merilä J, Kim Y, Mao K, López‐Pujol J, Chung MG. A review on
Q
ST
–
F
ST
comparisons of seed plants: Insights for conservation. Ecol Evol 2023; 13:e9926. [PMID: 37006890 PMCID: PMC10049885 DOI: 10.1002/ece3.9926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 02/14/2023] [Accepted: 03/02/2023] [Indexed: 03/30/2023] Open
Abstract
Increased access to genome-wide data provides new opportunities for plant conservation. However, information on neutral genetic diversity in a small number of marker loci can still be valuable because genomic data are not available to most rare plant species. In the hope of bridging the gap between conservation science and practice, we outline how conservation practitioners can more efficiently employ population genetic information in plant conservation. We first review the current knowledge about neutral genetic variation (NGV) and adaptive genetic variation (AGV) in seed plants, regarding both within-population and among-population components. We then introduce the estimates of among-population genetic differentiation in quantitative traits (Q ST) and neutral markers (F ST) to plant biology and summarize conservation applications derived from Q ST-F ST comparisons, particularly on how to capture most AGV and NGV on both in-situ and ex-situ programs. Based on a review of published studies, we found that, on average, two and four populations would be needed for woody perennials (n = 18) to capture 99% of NGV and AGV, respectively, whereas four populations would be needed in case of herbaceous perennials (n = 14). On average, Q ST is about 3.6, 1.5, and 1.1 times greater than F ST in woody plants, annuals, and herbaceous perennials, respectively. Hence, conservation and management policies or suggestions based solely on inference on F ST could be misleading, particularly in woody species. To maximize the preservation of the maximum levels of both AGV and NGV, we suggest using maximum Q ST rather than average Q ST. We recommend conservation managers and practitioners consider this when formulating further conservation and restoration plans for plant species, particularly woody species.
Collapse
Affiliation(s)
- Mi Yoon Chung
- Department of Biological SciencesChungnam National UniversityDaejeon34134South Korea
| | - Juha Merilä
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFI‐00014Finland
- Area of Ecology & BiodiversitySchool of Biological SciencesThe University of Hong KongHong Kong SARChina
| | - Yuseob Kim
- Division of EcoScienceEwha Womans UniversitySeoul03760South Korea
- Department of Life ScienceEwha Womans UniversitySeoul03760South Korea
| | - Kangshan Mao
- Key Laboratory for Bio‐resources and Eco‐environment of Ministry of Education, College of Life Science, State Key Laboratory of Hydraulics and Mountain River EngineeringSichuan UniversityChengdu610065China
| | - Jordi López‐Pujol
- Botanic Institute of Barcelona (IBB), CSIC‐Ajuntament de BarcelonaBarcelona08038CataloniaSpain
- Universidad Espíritu Santo (UEES)Samborondón091650Ecuador
| | - Myong Gi Chung
- Division of Life Science and RINSGyeongsang National UniversityJinju52828South Korea
| |
Collapse
|
34
|
Abstract
Insects constitute vital components of ecosystems. There is alarming evidence for global declines in insect species diversity, abundance, and biomass caused by anthropogenic drivers such as habitat degradation or loss, agricultural practices, climate change, and environmental pollution. This raises important concerns about human food security and ecosystem functionality and calls for more research to assess insect population trends and identify threatened species and the causes of declines to inform conservation strategies. Analysis of genetic diversity is a powerful tool to address these goals, but so far animal conservation genetics research has focused strongly on endangered vertebrates, devoting less attention to invertebrates, such as insects, that constitute most biodiversity. Insects' shorter generation times and larger population sizes likely necessitate different analytical methods and management strategies. The availability of high-quality reference genome assemblies enables population genomics to address several key issues. These include precise inference of past demographic fluctuations and recent declines, measurement of genetic load levels, delineation of evolutionarily significant units and cryptic species, and analysis of genetic adaptation to stressors. This enables identification of populations that are particularly vulnerable to future threats, considering their potential to adapt and evolve. We review the application of population genomics to insect conservation and the outlook for averting insect declines.
Collapse
Affiliation(s)
- Matthew T Webster
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden;
| | - Alexis Beaurepaire
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Eckart Stolle
- Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig, Bonn, Germany
| |
Collapse
|
35
|
Kelly JK. The genomic scale of fluctuating selection in a natural plant population. Evol Lett 2022; 6:506-521. [PMID: 36579169 PMCID: PMC9783439 DOI: 10.1002/evl3.308] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/08/2022] [Accepted: 11/13/2022] [Indexed: 12/30/2022] Open
Abstract
This study characterizes evolution at ≈1.86 million Single Nucleotide Polymorphisms (SNPs) within a natural population of yellow monkeyflower (Mimulus guttatus). Most SNPs exhibit minimal change over a span of 23 generations (less than 1% per year), consistent with neutral evolution in a large population. However, several thousand SNPs display strong fluctuations in frequency. Multiple lines of evidence indicate that these 'Fluctuating SNPs' are driven by temporally varying selection. Unlinked loci exhibit synchronous changes with the same allele increasing consistently in certain time intervals but declining in others. This synchrony is sufficiently pronounced that we can roughly classify intervals into two categories, "green" and "yellow," corresponding to conflicting selection regimes. Alleles increasing in green intervals are associated with early life investment in vegetative tissue and delayed flowering. The alternative alleles that increase in yellow intervals are associated with rapid progression to flowering. Selection on the Fluctuating SNPs produces a strong ripple effect on variation across the genome. Accounting for estimation error, we estimate the distribution of allele frequency change per generation in this population. While change is minimal for most SNPs, diffuse hitchhiking effects generated by selected loci may be driving neutral SNPs to a much greater extent than classic genetic drift.
Collapse
Affiliation(s)
- John K. Kelly
- Department of Ecology and Evolutionary BiologyUniversity of KansasLawrenceKansasUSA
| |
Collapse
|
36
|
Olazcuaga L, Foucaud J, Deschamps C, Loiseau A, Claret J, Vedovato R, Guilhot R, Sévely C, Gautier M, Hufbauer RA, Rode NO, Estoup A. Rapid and transient evolution of local adaptation to seasonal host fruits in an invasive pest fly. Evol Lett 2022; 6:490-505. [PMID: 36579160 PMCID: PMC9783429 DOI: 10.1002/evl3.304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 07/12/2022] [Accepted: 10/27/2022] [Indexed: 12/30/2022] Open
Abstract
Both local adaptation and adaptive phenotypic plasticity can influence the match between phenotypic traits and local environmental conditions. Theory predicts that environments stable for multiple generations promote local adaptation, whereas highly heterogeneous environments favor adaptive phenotypic plasticity. However, when environments have periods of stability mixed with heterogeneity, the relative importance of local adaptation and adaptive phenotypic plasticity is unclear. Here, we used Drosophila suzukii as a model system to evaluate the relative influence of genetic and plastic effects on the match of populations to environments with periods of stability from three to four generations. This invasive pest insect can develop within different fruits, and persists throughout the year in a given location on a succession of distinct host fruits, each one being available for only a few generations. Using reciprocal common environment experiments of natural D. suzukii populations collected from cherry, strawberry, and blackberry, we found that both oviposition preference and offspring performance were higher on medium made with the fruit from which the population originated than on media made with alternative fruits. This pattern, which remained after two generations in the laboratory, was analyzed using a statistical method we developed to quantify the contributions of local adaptation and adaptive plasticity in determining fitness. Altogether, we found that genetic effects (local adaptation) dominate over plastic effects (adaptive phenotypic plasticity). Our study demonstrates that spatially and temporally variable selection does not prevent the rapid evolution of local adaptation in natural populations. The speed and strength of adaptation may be facilitated by several mechanisms including a large effective population size and strong selective pressures imposed by host plants.
Collapse
Affiliation(s)
- Laure Olazcuaga
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France,Department of Agricultural BiologyColorado State UniversityFort CollinsColorado80523USA
| | - Julien Foucaud
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Candice Deschamps
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Anne Loiseau
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Jean‐Loup Claret
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Romain Vedovato
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Robin Guilhot
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Cyril Sévely
- Chambre d'agriculture de l'HéraultLattes34875France
| | - Mathieu Gautier
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Ruth A. Hufbauer
- Department of Agricultural BiologyColorado State UniversityFort CollinsColorado80523USA,Graduate Degree Program in EcologyColorado State UniversityFort CollinsColorado80523USA
| | - Nicolas O. Rode
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| | - Arnaud Estoup
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Univ MontpellierMontpellier34988France
| |
Collapse
|
37
|
Coughlan JM, Dagilis AJ, Serrato-Capuchina A, Elias H, Peede D, Isbell K, Castillo DM, Cooper BS, Matute DR. Patterns of Population Structure and Introgression Among Recently Differentiated Drosophila melanogaster Populations. Mol Biol Evol 2022; 39:msac223. [PMID: 36251862 PMCID: PMC9641974 DOI: 10.1093/molbev/msac223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Despite a century of genetic analysis, the evolutionary processes that have generated the patterns of exceptional genetic and phenotypic variation in the model organism Drosophila melanogaster remains poorly understood. In particular, how genetic variation is partitioned within its putative ancestral range in Southern Africa remains unresolved. Here, we study patterns of population genetic structure, admixture, and the spatial structuring of candidate incompatibility alleles across a global sample, including 223 new accessions, predominantly from remote regions in Southern Africa. We identify nine major ancestries, six that primarily occur in Africa and one that has not been previously described. We find evidence for both contemporary and historical admixture between ancestries, with admixture rates varying both within and between continents. For example, while previous work has highlighted an admixture zone between broadly defined African and European ancestries in the Caribbean and southeastern USA, we identify West African ancestry as the most likely African contributor. Moreover, loci showing the strongest signal of introgression between West Africa and the Caribbean/southeastern USA include several genes relating to neurological development and male courtship behavior, in line with previous work showing shared mating behaviors between these regions. Finally, while we hypothesized that potential incompatibility loci may contribute to population genetic structure across the range of D. melanogaster; these loci are, on average, not highly differentiated between ancestries. This work contributes to our understanding of the evolutionary history of a key model system, and provides insight into the partitioning of diversity across its range.
Collapse
Affiliation(s)
- Jenn M Coughlan
- Biology Department, University of North Carolina, Chapel Hill, NC, USA
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | - Andrius J Dagilis
- Biology Department, University of North Carolina, Chapel Hill, NC, USA
| | | | - Hope Elias
- Biology Department, University of North Carolina, Chapel Hill, NC, USA
| | - David Peede
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA
| | - Kristin Isbell
- Biology Department, University of North Carolina, Chapel Hill, NC, USA
| | - Dean M Castillo
- Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Brandon S Cooper
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Daniel R Matute
- Biology Department, University of North Carolina, Chapel Hill, NC, USA
| |
Collapse
|
38
|
Yu Y, Bergland AO. Distinct signals of clinal and seasonal allele frequency change at eQTLs in Drosophila melanogaster. Evolution 2022; 76:2758-2768. [PMID: 36097359 PMCID: PMC9710195 DOI: 10.1111/evo.14617] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 07/31/2022] [Accepted: 08/17/2022] [Indexed: 01/22/2023]
Abstract
Populations of short-lived organisms can respond to spatial and temporal environmental heterogeneity through local adaptation. Local adaptation can be reflected on both phenotypic and genetic levels, and it has been documented in many organisms. Although complex fitness-related phenotypes have been shown to vary across latitudinal clines and seasons in similar ways in Drosophila melanogaster populations, the comparative signals of local adaptation across space and time remain poorly understood. Here, we examined patterns of allele frequency change across a latitudinal cline and between seasons at previously reported expression quantitative trait loci (eQTLs). We divided eQTLs into groups by using differential expression profiles of fly populations collected across latitudinal clines or exposed to different environmental conditions. In general, we find that eQTLs are enriched for clinally varying polymorphisms, and that these eQTLs change in frequency in concordant ways across the cline and in response to starvation and chill-coma. The enrichment of eQTLs among seasonally varying polymorphisms is more subtle, and the direction of allele frequency change at eQTLs appears to be somewhat idiosyncratic. Taken together, we suggest that clinal adaptation at eQTLs is at least partially distinct from seasonal adaptation.
Collapse
Affiliation(s)
- Yang Yu
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginia22904
| | - Alan O. Bergland
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginia22904
| |
Collapse
|
39
|
Mayekar HV, Ramkumar DK, Garg D, Nair A, Khandelwal A, Joshi K, Rajpurohit S. Clinal variation as a tool to understand climate change. Front Physiol 2022; 13:880728. [PMID: 36304576 PMCID: PMC9593049 DOI: 10.3389/fphys.2022.880728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Clines are observable gradients that reflect continuous change in biological traits of species across geographical ranges. Clinal gradients could vary at geographic scales (latitude and altitude). Since clinal variations represent active genomic responses at the population level they (clines) provide an immense power to address questions related to climatic change. With the fast pace of climate change i.e. warming, populations are also likely to exhibit rapid responses; at both the phenotypic and genotypic levels. We seek to understand how clinal variation could be used to anticipate climatic responses using Drosophila, a pervasively used inter-disciplinary model system owing to its molecular repertoire. The genomic information coupled with the phenotypic variation greatly facilitates our understanding of the Drosophilidae response to climate change. We discuss traits associated with clinal variation at the phenotypic level as well as their underlying genetic regulators. Given prevailing climatic conditions and future projections for climate change, clines could emerge as monitoring tools to track the cross-talk between climatic variables and organisms.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Subhash Rajpurohit
- Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Ahmedabad, GJ, India
| |
Collapse
|
40
|
Diamond SE, Martin RA, Bellino G, Crown KN, Prileson EG. Urban evolution of thermal physiology in a range-expanding, mycophagous fruit fly, Drosophila tripunctata. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
In Drosophila spp., their often high number of annual generations, large population sizes and large amounts of standing genetic variation should predispose them to undergo contemporary adaptation to climatic warming. However, a number of laboratory experimental evolution studies in this group of organisms suggest strong limits on the rate and magnitude of contemporary thermal adaptation. Here, we explore this discrepancy by examining the potential for rapid evolutionary divergence between wild populations of Drosophila tripunctata Loew, 1862 from rural and urban sites. We performed a multi-generation common garden study and found evidence for the evolution of higher heat tolerance (critical thermal maximum) in flies from urban populations. We also detected evolutionary divergence in cold resistance (chill coma recovery time), with diminished cold resistance in flies from urban populations, although the effect was weaker than the shift in heat tolerance. Our study provides evidence of contemporary urban thermal adaptation, although the magnitude of phenotypic change lagged the magnitude of environmental temperature change across the urbanization gradient, suggesting potential limits on the evolution of urban thermal physiology.
Collapse
Affiliation(s)
- Sarah E Diamond
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - Ryan A Martin
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - Grace Bellino
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - K Nicole Crown
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| | - Eric G Prileson
- Department of Biology, Case Western Reserve University , Cleveland, OH 44106 , USA
| |
Collapse
|
41
|
Önder BŞ, Aksoy CF. Seasonal variation in wing size and shape of Drosophila melanogaster reveals rapid adaptation to environmental changes. Sci Rep 2022; 12:14622. [PMID: 36028640 PMCID: PMC9418266 DOI: 10.1038/s41598-022-18891-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/22/2022] [Indexed: 11/10/2022] Open
Abstract
Populations in seasonal fluctuating environments receive multiple environmental cues and must deal with this heterogenic environment to survive and reproduce. An enlarged literature shows that this situation can be resolved through rapid adaptation in Drosophila melanogaster populations. Long-term monitoring of a population in its natural habitat and quantitative measurement of its responses to seasonal environmental changes are important for understanding the adaptive response of D. melanogaster to temporal variable selection. Here, we use inbred lines of a D. melanogaster population collected at monthly intervals between May to October over a temporal scale spanning three consecutive years to understand the variation in wing size and wing shape over these timepoints. The wing size and shape of this population changed significantly between months and a seasonal cycle of this traits is repeated for three years. Our results suggest that the effects of environmental variables that generated variation in body size between populations such as latitudinal clines, are a selective pressure in a different manner in terms of seasonal variation. Temperature related variable have a significant nonlinear relation to this fluctuating pattern in size and shape, whereas precipitation and humidity have a sex-specific effect which is more significant in males.
Collapse
Affiliation(s)
- Banu Şebnem Önder
- Genetic Variation and Adaptation Laboratory, Department of Biology, Faculty of Science, Hacettepe University, Ankara, Turkey.
| | - Cansu Fidan Aksoy
- Genetic Variation and Adaptation Laboratory, Department of Biology, Faculty of Science, Hacettepe University, Ankara, Turkey
| |
Collapse
|
42
|
Fuad MTI, Shi W, Liao X, Li Y, Sharifuzzaman S, Zhang X, Liu X, Xu Q. Transcriptomic response of intertidal brittle star Ophiothrix exigua to seasonal variation. Mar Genomics 2022; 64:100957. [DOI: 10.1016/j.margen.2022.100957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 05/06/2022] [Accepted: 05/08/2022] [Indexed: 11/28/2022]
|
43
|
Delph LF, Brown KE, Ríos LD, Kelly JK. Sex‐specific natural selection on SNPs in
Silene latifolia. Evol Lett 2022; 6:308-318. [PMID: 35937470 PMCID: PMC9346077 DOI: 10.1002/evl3.283] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 02/24/2022] [Accepted: 03/13/2022] [Indexed: 01/15/2023] Open
Affiliation(s)
- Lynda F. Delph
- Department of Biology Indiana University Bloomington Indiana USA
| | - Keely E. Brown
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence Kansas USA
| | - Luis Diego Ríos
- Department of Biology Indiana University Bloomington Indiana USA
| | - John K. Kelly
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence Kansas USA
| |
Collapse
|
44
|
Abstract
Selection in fruit flies leads to fast adaption to seasonal changes.
Collapse
Affiliation(s)
- Ary H Hoffmann
- School of BioSciences, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| |
Collapse
|
45
|
Rudman SM, Greenblum SI, Rajpurohit S, Betancourt NJ, Hanna J, Tilk S, Yokoyama T, Petrov DA, Schmidt P. Direct observation of adaptive tracking on ecological time scales in Drosophila. Science 2022; 375:eabj7484. [PMID: 35298245 PMCID: PMC10684103 DOI: 10.1126/science.abj7484] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Direct observation of evolution in response to natural environmental change can resolve fundamental questions about adaptation, including its pace, temporal dynamics, and underlying phenotypic and genomic architecture. We tracked the evolution of fitness-associated phenotypes and allele frequencies genome-wide in 10 replicate field populations of Drosophila melanogaster over 10 generations from summer to late fall. Adaptation was evident over each sampling interval (one to four generations), with exceptionally rapid phenotypic adaptation and large allele frequency shifts at many independent loci. The direction and basis of the adaptive response shifted repeatedly over time, consistent with the action of strong and rapidly fluctuating selection. Overall, we found clear phenotypic and genomic evidence of adaptive tracking occurring contemporaneously with environmental change, thus demonstrating the temporally dynamic nature of adaptation.
Collapse
Affiliation(s)
- Seth M. Rudman
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
- School of Biological Sciences, Washington State University, Vancouver, WA 98686, USA
| | - Sharon I. Greenblum
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Subhash Rajpurohit
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Biological and Life Sciences, Ahmedabad University, Ahmedabad 380009, GJ, India
| | | | - Jinjoo Hanna
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Susanne Tilk
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Tuya Yokoyama
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Dmitri A. Petrov
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Paul Schmidt
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
46
|
Lirakis M, Nolte V, Schlötterer C. Pool-GWAS on reproductive dormancy in Drosophila simulans suggests a polygenic architecture. G3 GENES|GENOMES|GENETICS 2022; 12:6523974. [PMID: 35137042 PMCID: PMC8895979 DOI: 10.1093/g3journal/jkac027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/29/2021] [Indexed: 11/29/2022]
Abstract
The genetic basis of adaptation to different environments has been of long-standing interest to evolutionary biologists. Dormancy is a well-studied adaptation to facilitate overwintering. In Drosophila melanogaster, a moderate number of genes with large effects have been described, which suggests a simple genetic basis of dormancy. On the other hand, genome-wide scans for dormancy suggest a polygenic architecture in insects. In D. melanogaster, the analysis of the genetic architecture of dormancy is complicated by the presence of cosmopolitan inversions. Here, we performed a genome-wide scan to characterize the genetic basis of this ecologically extremely important trait in the sibling species of D. melanogaster, D. simulans that lacks cosmopolitan inversions. We performed Pool-GWAS in a South African D. simulans population for dormancy incidence at 2 temperature regimes (10 and 12°C, LD 10:14). We identified several genes with SNPs that showed a significant association with dormancy (P-value < 1e-13), but the overall modest response suggests that dormancy is a polygenic trait with many loci of small effect. Our results shed light on controversies on reproductive dormancy in Drosophila and have important implications for the characterization of the genetic basis of this trait.
Collapse
Affiliation(s)
- Manolis Lirakis
- Institut für Populationsgenetik, Vetmeduni Vienna, 1210 Wien, Austria
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, 1210 Wien, Austria
| | - Viola Nolte
- Institut für Populationsgenetik, Vetmeduni Vienna, 1210 Wien, Austria
| | | |
Collapse
|
47
|
Temperature effects on cellular host-microbe interactions explain continent-wide endosymbiont prevalence. Curr Biol 2022; 32:878-888.e8. [PMID: 34919808 PMCID: PMC8891084 DOI: 10.1016/j.cub.2021.11.065] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/09/2021] [Accepted: 11/26/2021] [Indexed: 01/03/2023]
Abstract
Endosymbioses influence host physiology, reproduction, and fitness, but these relationships require efficient microbe transmission between host generations to persist. Maternally transmitted Wolbachia are the most common known endosymbionts,1 but their frequencies vary widely within and among host populations for unknown reasons.2,3 Here, we integrate genomic, cellular, and phenotypic analyses with mathematical models to provide an unexpectedly simple explanation for global wMel Wolbachia prevalence in Drosophila melanogaster. Cooling temperatures decrease wMel cellular abundance at a key stage of host oogenesis, producing temperature-dependent variation in maternal transmission that plausibly explains latitudinal clines of wMel frequencies on multiple continents. wMel sampled from a temperate climate targets the germline more efficiently in the cold than a recently differentiated tropical variant (∼2,200 years ago), indicative of rapid wMel adaptation to climate. Genomic analyses identify a very narrow list of wMel alleles-most notably, a derived stop codon in the major Wolbachia surface protein WspB-that underlie thermal sensitivity of cellular Wolbachia abundance and covary with temperature globally. Decoupling temperate wMel and host genomes further reduces transmission in the cold, a pattern that is characteristic of host-microbe co-adaptation to a temperate climate. Complex interactions among Wolbachia, hosts, and the environment (GxGxE) mediate wMel cellular abundance and maternal transmission, implicating temperature as a key determinant of Wolbachia spread and equilibrium frequencies, in conjunction with Wolbachia effects on host fitness and reproduction.4,5 Our results motivate the strategic use of locally selected wMel variants for Wolbachia-based biocontrol efforts, which protect millions of individuals from arboviruses that cause human disease.6.
Collapse
|
48
|
Hoikkala A, Poikela N. Adaptation and ecological speciation in seasonally varying environments at high latitudes: Drosophila virilis group. Fly (Austin) 2022; 16:85-104. [PMID: 35060806 PMCID: PMC8786326 DOI: 10.1080/19336934.2021.2016327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Living in high latitudes and altitudes sets specific requirements on species’ ability to forecast seasonal changes and to respond to them in an appropriate way. Adaptation into diverse environmental conditions can also lead to ecological speciation through habitat isolation or by inducing changes in traits that influence assortative mating. In this review, we explain how the unique time-measuring systems of Drosophila virilis group species have enabled the species to occupy high latitudes and how the traits involved in species reproduction and survival exhibit strong linkage with latitudinally varying photoperiodic and climatic conditions. We also describe variation in reproductive barriers between the populations of two species with overlapping distributions and show how local adaptation and the reinforcement of prezygotic barriers have created partial reproductive isolation between conspecific populations. Finally, we consider the role of species-specific chromosomal inversions and the X chromosome in the development of reproductive barriers between diverging lineages.
Collapse
Affiliation(s)
- Anneli Hoikkala
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Noora Poikela
- Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| |
Collapse
|
49
|
Abrams MB, Brem RB. Temperature-dependent genetics of thermotolerance between yeast species. Front Ecol Evol 2022; 10:859904. [PMID: 36911365 PMCID: PMC10004143 DOI: 10.3389/fevo.2022.859904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many traits of industrial and basic biological interest arose long ago, and manifest now as fixed differences between a focal species and its reproductively isolated relatives. In these systems, extant individuals can hold clues to the mechanisms by which phenotypes evolved in their ancestors. We harnessed yeast thermotolerance as a test case for such molecular-genetic inferences. In viability experiments, we showed that extant Saccharomyces cerevisiae survived at temperatures where cultures of its sister species S. paradoxus died out. Then, focusing on loci that contribute to this difference, we found that the genetic mechanisms of high-temperature growth changed with temperature. We also uncovered an enrichment of low-frequency variants at thermotolerance loci in S. cerevisiae population sequences, suggestive of a history of non-neutral selective forces acting at these genes. We interpret these results in light of models of the evolutionary mechanisms by which the thermotolerance trait arose in the S. cerevisiae lineage. Together, our results and interpretation underscore the power of genetic approaches to explore how an ancient trait came to be.
Collapse
Affiliation(s)
- Melanie B Abrams
- UC Berkeley, Department of Plant and Microbial Biology, Berkeley, CA, USA
| | - Rachel B Brem
- UC Berkeley, Department of Plant and Microbial Biology, Berkeley, CA, USA
| |
Collapse
|
50
|
Lange JD, Bastide H, Lack JB, Pool JE. A Population Genomic Assessment of Three Decades of Evolution in a Natural Drosophila Population. Mol Biol Evol 2021; 39:6491261. [PMID: 34971382 PMCID: PMC8826484 DOI: 10.1093/molbev/msab368] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Population genetics seeks to illuminate the forces shaping genetic variation, often based on a single snapshot of genomic variation. However, utilizing multiple sampling times to study changes in allele frequencies can help clarify the relative roles of neutral and non-neutral forces on short time scales. This study compares whole-genome sequence variation of recently collected natural population samples of Drosophila melanogaster against a collection made approximately 35 years prior from the same locality—encompassing roughly 500 generations of evolution. The allele frequency changes between these time points would suggest a relatively small local effective population size on the order of 10,000, significantly smaller than the global effective population size of the species. Some loci display stronger allele frequency changes than would be expected anywhere in the genome under neutrality—most notably the tandem paralogs Cyp6a17 and Cyp6a23, which are impacted by structural variation associated with resistance to pyrethroid insecticides. We find a genome-wide excess of outliers for high genetic differentiation between old and new samples, but a larger number of adaptation targets may have affected SNP-level differentiation versus window differentiation. We also find evidence for strengthening latitudinal allele frequency clines: northern-associated alleles have increased in frequency by an average of nearly 2.5% at SNPs previously identified as clinal outliers, but no such pattern is observed at random SNPs. This project underscores the scientific potential of using multiple sampling time points to investigate how evolution operates in natural populations, by quantifying how genetic variation has changed over ecologically relevant timescales.
Collapse
Affiliation(s)
- Jeremy D Lange
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Héloïse Bastide
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Justin B Lack
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - John E Pool
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| |
Collapse
|