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Wang Y, McNeil P, Abdulazeez R, Pascual M, Johnston SE, Keightley PD, Obbard DJ. Variation in mutation, recombination, and transposition rates in Drosophila melanogaster and Drosophila simulans. Genome Res 2023; 33:587-598. [PMID: 37037625 PMCID: PMC10234296 DOI: 10.1101/gr.277383.122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 03/28/2023] [Indexed: 04/12/2023]
Abstract
The rates of mutation, recombination, and transposition are core parameters in models of evolution. They impact genetic diversity, responses to ongoing selection, and levels of genetic load. However, even for key evolutionary model species such as Drosophila melanogaster and Drosophila simulans, few estimates of these parameters are available, and we have little idea of how rates vary between individuals, sexes, or populations. Knowledge of this variation is fundamental for parameterizing models of genome evolution. Here, we provide direct estimates of mutation, recombination, and transposition rates and their variation in a West African and a European population of D. melanogaster and a European population of D. simulans Across 89 flies, we observe 58 single-nucleotide mutations, 286 crossovers, and 89 transposable element (TE) insertions. Compared to the European D. melanogaster, we find the West African population has a lower mutation rate (1.67 × 10-9 site-1 gen-1 vs. 4.86 × 10-9 site-1 gen-1) and a lower transposition rate (8.99 × 10-5 copy-1 gen-1 vs. 23.36 × 10-5 copy-1 gen-1), but a higher recombination rate (3.44 cM/Mb vs. 2.06 cM/Mb). The European D. simulans population has a similar mutation rate to European D. melanogaster, but a significantly higher recombination rate and a lower, but not significantly different, transposition rate. Overall, we find paternal-derived mutations are more frequent than maternal ones in both species. Our study quantifies the variation in rates of mutation, recombination, and transposition among different populations and sexes, and our direct estimates of these parameters in D. melanogaster and D. simulans will benefit future studies in population and evolutionary genetics.
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Affiliation(s)
- Yiguan Wang
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom;
| | - Paul McNeil
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | | | - Marta Pascual
- Departament de Genètica, Microbiologia i Estadística and IRBio, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Susan E Johnston
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Peter D Keightley
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Darren J Obbard
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
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Horváth V, Guirao-Rico S, Salces-Ortiz J, Rech GE, Green L, Aprea E, Rodeghiero M, Anfora G, González J. Gene expression differences consistent with water loss reduction underlie desiccation tolerance of natural Drosophila populations. BMC Biol 2023; 21:35. [PMID: 36797754 PMCID: PMC9933328 DOI: 10.1186/s12915-023-01530-4] [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] [Received: 05/23/2022] [Accepted: 01/27/2023] [Indexed: 02/18/2023] Open
Abstract
BACKGROUND Climate change is one of the main factors shaping the distribution and biodiversity of organisms, among others by greatly altering water availability, thus exposing species and ecosystems to harsh desiccation conditions. However, most of the studies so far have focused on the effects of increased temperature. Integrating transcriptomics and physiology is key to advancing our knowledge on how species cope with desiccation stress, and these studies are still best accomplished in model organisms. RESULTS Here, we characterized the natural variation of European D. melanogaster populations across climate zones and found that strains from arid regions were similar or more tolerant to desiccation compared with strains from temperate regions. Tolerant and sensitive strains differed not only in their transcriptomic response to stress but also in their basal expression levels. We further showed that gene expression changes in tolerant strains correlated with their physiological response to desiccation stress and with their cuticular hydrocarbon composition, and functionally validated three of the candidate genes identified. Transposable elements, which are known to influence stress response across organisms, were not found to be enriched nearby differentially expressed genes. Finally, we identified several tRNA-derived small RNA fragments that differentially targeted genes in response to desiccation stress. CONCLUSIONS Overall, our results showed that basal gene expression differences across individuals should be analyzed if we are to understand the genetic basis of differential stress survival. Moreover, tRNA-derived small RNA fragments appear to be relevant across stress responses and allow for the identification of stress-response genes not detected at the transcriptional level.
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Affiliation(s)
- Vivien Horváth
- Institute of Evolutionary Biology, CSIC, UPF, Barcelona, Spain
| | | | | | - Gabriel E Rech
- Institute of Evolutionary Biology, CSIC, UPF, Barcelona, Spain
| | - Llewellyn Green
- Institute of Evolutionary Biology, CSIC, UPF, Barcelona, Spain
| | - Eugenio Aprea
- Agriculture Food Environment Centre (C3A), University of Trento, San Michele All'adige (TN), Italy
- Research and Innovation Centre, Fondazione Edmund Mach, San Michele All'adige (TN), Italy
| | - Mirco Rodeghiero
- Agriculture Food Environment Centre (C3A), University of Trento, San Michele All'adige (TN), Italy
- Research and Innovation Centre, Fondazione Edmund Mach, San Michele All'adige (TN), Italy
| | - Gianfranco Anfora
- Agriculture Food Environment Centre (C3A), University of Trento, San Michele All'adige (TN), Italy
- Research and Innovation Centre, Fondazione Edmund Mach, San Michele All'adige (TN), Italy
| | - Josefa González
- Institute of Evolutionary Biology, CSIC, UPF, Barcelona, Spain.
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Pfenninger M, Foucault Q. Population Genomic Time Series Data of a Natural Population Suggests Adaptive Tracking of Fluctuating Environmental Changes. Integr Comp Biol 2022; 62:1812-1826. [PMID: 35762661 DOI: 10.1093/icb/icac098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 06/07/2022] [Accepted: 06/16/2022] [Indexed: 01/05/2023] Open
Abstract
Natural populations are constantly exposed to fluctuating environmental changes that negatively affect their fitness in unpredictable ways. While theoretical models show the possibility of counteracting these environmental changes through rapid evolutionary adaptations, there have been few empirical studies demonstrating such adaptive tracking in natural populations. Here, we analyzed environmental data, fitness-related phenotyping and genomic time-series data sampled over 3 years from a natural Chironomus riparius (Diptera, Insecta) population to address this question. We show that the population's environment varied significantly on the time scale of the sampling in many selectively relevant dimensions, independently of each other. Similarly, phenotypic fitness components evolved significantly on the same temporal scale (mean 0.32 Haldanes), likewise independent from each other. The allele frequencies of 367,446 SNPs across the genome showed evidence of positive selection. Using temporal correlation of spatially coherent allele frequency changes revealed 35,574 haplotypes with more than one selected SNP. The mean selection coefficient for these haplotypes was 0.30 (s.d. = 0.68). The frequency changes of these haplotypes clustered in 46 different temporal patterns, indicating concerted, independent evolution of many polygenic traits. Nine of these patterns were strongly correlated with measured environmental variables. Enrichment analysis of affected genes suggested the implication of a wide variety of biological processes. Thus, our results suggest overall that the natural population of C. riparius tracks environmental change through rapid polygenic adaptation in many independent dimensions. This is further evidence that natural selection is pervasive at the genomic level and that evolutionary and ecological time scales may not differ at all, at least in some organisms.
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Affiliation(s)
- Markus Pfenninger
- Department Molecular Ecology, Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, 60325 Frankfurt am Main, Germany.,Institute for Molecular and Organismic Evolution, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 7, 55128 Mainz, Germany.,LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, 60325 Frankfurt am Main, Germany
| | - Quentin Foucault
- Department Molecular Ecology, Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, 60325 Frankfurt am Main, Germany.,Institute for Molecular and Organismic Evolution, Johannes Gutenberg University, Johann-Joachim-Becher-Weg 7, 55128 Mainz, Germany
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Rybnikov S, Weissman DB, Hübner S, Korol AB. Fitness dependence preserves selection for recombination across diverse mixed mating strategies. J Theor Biol 2021; 528:110849. [PMID: 34331961 DOI: 10.1016/j.jtbi.2021.110849] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/13/2021] [Accepted: 07/24/2021] [Indexed: 12/16/2022]
Abstract
Meiotic recombination and the factors affecting its rate and fate in nature have inspired many studies in theoretical evolutionary biology. Classical theoretical models have inferred that recombination can be favored under a rather restricted parameter range. Thus, the ubiquity of recombination in nature remains an open question. However, these models assumed constant recombination with an equal rate across all individuals within the population, whereas empirical evidence suggests that recombination may display certain sensitivity to ecological stressors and/or genotype fitness. Models assuming condition-dependent recombination show that such a strategy can often be favored over constant recombination. Moreover, in our recent model with panmictic populations subjected to purifying selection, fitness-dependent recombination was quite often favored even when any constant recombination was rejected. By using numerical modeling, we test whether such a 'recombination-rescuing potential' of fitness dependence holds also beyond panmixia, given the recognized effect of mating strategy on the evolution of recombination. We show that deviations from panmixia generally increase the recombination-rescuing potential of fitness dependence, with the strongest effect under intermediate selfing or high clonality. We find that under partial clonality, the evolutionary advantage of fitness-dependent recombination is determined mostly by selection against heterozygotes and additive-by-additive epistasis, while under partial selfing, additive-by-dominance epistasis is also a driver.
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Affiliation(s)
- Sviatoslav Rybnikov
- Institute of Evolution, University of Haifa, Haifa 3498838, Israel; Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 3498838, Israel.
| | | | - Sariel Hübner
- Institute of Evolution, University of Haifa, Haifa 3498838, Israel; Galilee Research Institute (MIGAL), Tel-Hai College, Upper Galilee 1220800, Israel
| | - Abraham B Korol
- Institute of Evolution, University of Haifa, Haifa 3498838, Israel; Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 3498838, Israel
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