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Kreiner JM, Hnatovska S, Stinchcombe JR, Wright SI. Quantifying the role of genome size and repeat content in adaptive variation and the architecture of flowering time in Amaranthus tuberculatus. PLoS Genet 2023; 19:e1010865. [PMID: 38150485 PMCID: PMC10775983 DOI: 10.1371/journal.pgen.1010865] [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: 07/12/2023] [Revised: 01/09/2024] [Accepted: 12/11/2023] [Indexed: 12/29/2023] Open
Abstract
Genome size variation, largely driven by repeat content, is poorly understood within and among populations, limiting our understanding of its significance for adaptation. Here we characterize intraspecific variation in genome size and repeat content across 186 individuals of Amaranthus tuberculatus, a ubiquitous native weed that shows flowering time adaptation to climate across its range and in response to agriculture. Sequence-based genome size estimates vary by up to 20% across individuals, consistent with the considerable variability in the abundance of transposable elements, unknown repeats, and rDNAs across individuals. The additive effect of this variation has important phenotypic consequences-individuals with more repeats, and thus larger genomes, show slower flowering times and growth rates. However, compared to newly-characterized gene copy number and polygenic nucleotide changes underlying variation in flowering time, we show that genome size is a marginal contributor. Differences in flowering time are reflected by genome size variation across sexes and marginally, habitats, while polygenic variation and a gene copy number variant within the ATP synthesis pathway show consistently stronger environmental clines than genome size. Repeat content nonetheless shows non-neutral distributions across the genome, and across latitudinal and environmental gradients, demonstrating the numerous governing processes that in turn influence quantitative genetic variation for phenotypes key to plant adaptation.
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Affiliation(s)
- Julia M. Kreiner
- Department of Botany, Biodiversity Research Centre, University of British Columbia
- Department of Ecology & Evolutionary Biology, University of Toronto
| | - Solomiya Hnatovska
- Department of Ecology & Evolutionary Biology, University of Toronto
- Department of Molecular Genetics, University of Toronto
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2
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Winbush A, Singh ND. Variation in fine-scale recombination rate in temperature-evolved Drosophila melanogaster populations in response to selection. G3 GENES|GENOMES|GENETICS 2022; 12:6663992. [PMID: 35961026 PMCID: PMC9526048 DOI: 10.1093/g3journal/jkac208] [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: 06/09/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022]
Abstract
Meiotic recombination plays a critical evolutionary role in maintaining fitness in response to selective pressures due to changing environments. Variation in recombination rate has been observed amongst and between species and populations and within genomes across numerous taxa. Studies have demonstrated a link between changes in recombination rate and selection, but the extent to which fine-scale recombination rate varies between evolved populations during the evolutionary period in response to selection is under active research. Here, we utilize a set of 3 temperature-evolved Drosophila melanogaster populations that were shown to have diverged in several phenotypes, including recombination rate, based on the temperature regime in which they evolved. Using whole-genome sequencing data from these populations, we generated linkage disequilibrium-based fine-scale recombination maps for each population. With these maps, we compare recombination rates and patterns among the 3 populations and show that they have diverged at fine scales but are conserved at broader scales. We further demonstrate a correlation between recombination rates and genomic variation in the 3 populations. Lastly, we show variation in localized regions of enhanced recombination rates, termed warm spots, between the populations with these warm spots and associated genes overlapping areas previously shown to have diverged in the 3 populations due to selection. These data support the existence of recombination modifiers in these populations which are subject to selection during evolutionary change.
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Affiliation(s)
- Ari Winbush
- Department of Biology, Institute of Ecology and Evolution, University of Oregon , Eugene, OR 97403, USA
| | - Nadia D Singh
- Department of Biology, Institute of Ecology and Evolution, University of Oregon , Eugene, OR 97403, USA
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3
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Altindag UH, Taylor HN, Shoben C, Pownall KA, Stevison LS. Putative Condition-Dependent Viability Selection in Wild-Type Stocks of <b><i>Drosophila pseudoobscura</i></b>. Cytogenet Genome Res 2022; 162:76-93. [DOI: 10.1159/000522585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 02/04/2022] [Indexed: 11/19/2022] Open
Abstract
Meiotic recombination rates vary in response to intrinsic and extrinsic factors. Recently, heat stress has been shown to reveal plasticity in recombination rates in <i>Drosophila pseudoobscura.</i> Here, a combination of molecular genotyping and X-linked recessive phenotypic markers were used to investigate differences in recombination rates due to heat stress. In addition, haplotypes from the genetic crosses were compared to test if they deviated from equal proportions, which would indicate viability selection. To avoid this potential bias, SNP genotyping markers overlapping the regions assayed with mutant markers were used to further investigate recombination rate. Interestingly, skews in haplotype frequency were consistent with the fixation of alleles in the wild-type stocks used that are unfit at high temperature. Evidence of viability selection due to heat stress in the wild-type haplotypes was most apparent on days 7–9 when more mutant non-crossover haplotypes were recovered in comparison to wild type (<i>p</i> < 0.0001). Recombination analysis using SNP markers showed days 9–10 as significantly different due to heat stress in 2 pairs of consecutive SNP markers (<i>p</i> = 0.018; <i>p</i> = 0.015), suggesting that during this time period the recombination rate is most sensitive to heat stress. This peak timing for recombination plasticity is consistent with <i>Drosophila melanogaster</i> based on a comparison of similarly timed key meiotic events, enabling future mechanistic work of temperature stress on recombination rate.
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4
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Mostoufi SL, Singh ND. Diet-induced changes in titer support a discrete response of Wolbachia-associated plastic recombination in Drosophila melanogaster. G3 GENES|GENOMES|GENETICS 2022; 12:6428536. [PMID: 34791181 PMCID: PMC8728003 DOI: 10.1093/g3journal/jkab375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022]
Abstract
Plastic recombination in Drosophila melanogaster has been associated with a variety of extrinsic and intrinsic factors such as temperature, starvation, and parasite infection. The bacterial endosymbiont Wolbachia pipientis has also been associated with plastic recombination in D. melanogaster. Wolbachia infection is pervasive in arthropods and this infection induces a variety of phenotypes in its hosts, the strength of which can depend on bacterial titer. Here, we test the hypothesis that the magnitude of Wolbachia-associated plastic recombination in D. melanogaster depends on titer. To manipulate titer, we raised Wolbachia-infected and uninfected flies on diets that have previously been shown to increase or decrease Wolbachia titer relative to controls. We measured recombination in treated and control individuals using a standard backcrossing scheme with two X-linked visible markers. Our results recapitulate previous findings that Wolbachia infection is associated with increased recombination rate across the yellow-vermillion interval of the X chromosome. Our data show no significant effect of diet or diet by Wolbachia interactions on recombination, suggesting that diet-induced changes in Wolbachia titer have no effect on the magnitude of plastic recombination. These findings represent one of the first steps toward investigating Wolbachia-associated plastic recombination and demonstrate that the phenotype is a discrete response rather than a continuous one.
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Affiliation(s)
- Sabrina L Mostoufi
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA
| | - Nadia D Singh
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA
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5
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Weitz AP, Dukic M, Zeitler L, Bomblies K. Male meiotic recombination rate varies with seasonal temperature fluctuations in wild populations of autotetraploid Arabidopsis arenosa. Mol Ecol 2021; 30:4630-4641. [PMID: 34273213 PMCID: PMC9292783 DOI: 10.1111/mec.16084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 12/16/2022]
Abstract
Meiosis, the cell division by which eukaryotes produce haploid gametes, is essential for fertility in sexually reproducing species. This process is sensitive to temperature, and can fail outright at temperature extremes. At less extreme values, temperature affects the genome‐wide rate of homologous recombination, which has important implications for evolution and population genetics. Numerous studies in laboratory conditions have shown that recombination rate plasticity is common, perhaps nearly universal, among eukaryotes. These studies have also shown that variation in the length or timing of stresses can strongly affect results, raising the important question whether these findings translate to more variable field conditions. Moreover, lower or higher recombination rate could cause certain kinds of meiotic aberrations, especially in polyploid species—raising the additional question whether temperature fluctuations in field conditions cause problems. Here, we tested whether (1) recombination rate varies across a season in the wild in two natural populations of autotetraploid Arabidopsis arenosa, (2) whether recombination rate correlates with temperature fluctuations in nature, and (3) whether natural temperature fluctuations might cause meiotic aberrations. We found that plants in two genetically distinct populations showed a similar plastic response with recombination rate increases correlated with both high and low temperatures. In addition, increased recombination rate correlated with increased multivalent formation, especially at lower temperature, hinting that polyploids in particular may suffer meiotic problems in conditions they encounter in nature. Our results show that studies of recombination rate plasticity done in laboratory settings inform our understanding of what happens in nature.
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Affiliation(s)
- Andrew P Weitz
- Department of Biology, Institute of Molecular Plant Biology, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland.,Department of Environmental Sciences, Western Washington University, Bellingham, Washington, USA
| | - Marinela Dukic
- Department of Biology, Institute of Molecular Plant Biology, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
| | - Leo Zeitler
- Department of Biology, Institute of Molecular Plant Biology, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland.,Department of Biology, Ecological Genomics, Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Kirsten Bomblies
- Department of Biology, Institute of Molecular Plant Biology, Swiss Federal Institute of Technology (ETH) Zürich, Zürich, Switzerland
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6
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Winbush A, Singh ND. Genomics of Recombination Rate Variation in Temperature-Evolved Drosophila melanogaster Populations. Genome Biol Evol 2020; 13:6008691. [PMID: 33247719 PMCID: PMC7851596 DOI: 10.1093/gbe/evaa252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Meiotic recombination is a critical process that ensures proper segregation of chromosome homologs through DNA double-strand break repair mechanisms. Rates of recombination are highly variable among various taxa, within species, and within genomes with far-reaching evolutionary and genomic consequences. The genetic basis of recombination rate variation is therefore crucial in the study of evolutionary biology but remains poorly understood. In this study, we took advantage of a set of experimental temperature-evolved populations of Drosophila melanogaster with heritable differences in recombination rates depending on the temperature regime in which they evolved. We performed whole-genome sequencing and identified several chromosomal regions that appear to be divergent depending on temperature regime. In addition, we identify a set of single-nucleotide polymorphisms and associated genes with significant differences in allele frequency when the different temperature populations are compared. Further refinement of these gene candidates emphasizing those expressed in the ovary and associated with DNA binding reveals numerous potential candidate genes such as Hr38, EcR, and mamo responsible for observed differences in recombination rates in these experimental evolution lines thus providing insight into the genetic basis of recombination rate variation.
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Affiliation(s)
- Ari Winbush
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, USA
| | - Nadia D Singh
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, USA
- Corresponding author: E-mail:
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7
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Howie JM, Mazzucco R, Taus T, Nolte V, Schlötterer C. DNA Motifs Are Not General Predictors of Recombination in Two Drosophila Sister Species. Genome Biol Evol 2019; 11:1345-1357. [PMID: 30980655 PMCID: PMC6490297 DOI: 10.1093/gbe/evz082] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2019] [Indexed: 12/11/2022] Open
Abstract
Meiotic recombination is crucial for chromosomal segregation and facilitates the spread of beneficial and removal of deleterious mutations. Recombination rates frequently vary along chromosomes and Drosophila melanogaster exhibits a remarkable pattern. Recombination rates gradually decrease toward centromeres and telomeres, with a dramatic impact on levels of variation in natural populations. Two close sister species, Drosophila simulans and Drosophila mauritiana do not only have higher recombination rates but also exhibit a much more homogeneous recombination rate that only drops sharply very close to centromeres and telomeres. Because certain sequence motifs are associated with recombination rate variation in D. melanogaster, we tested whether the difference in recombination landscape between D. melanogaster and D. simulans can be explained by the genomic distribution of recombination rate–associated sequence motifs. We constructed the first high-resolution recombination map for D. simulans based on 189 haplotypes from a natural D. simulans population and searched for short sequence motifs linked with higher than average recombination in both sister species. We identified five consensus motifs significantly associated with higher than average chromosome-wide recombination rates in at least one species and present in both. Testing fine resolution associations between motif density and recombination, we found strong and positive associations genome-wide over a range of scales in D. melanogaster, while the results were equivocal in D. simulans. Despite the strong association in D. melanogaster, we did not find a decreasing density of these short-repeat motifs toward centromeres and telomeres. We conclude that the density of recombination-associated repeat motifs cannot explain the large-scale recombination landscape in D. melanogaster, nor the differences to D. simulans. The strong association seen for the sequence motifs in D. melanogaster likely reflects their impact influencing local differences in recombination rates along the genome.
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Affiliation(s)
- James M Howie
- Institut für Populationsgenetik, Vetmeduni Vienna, Austria
| | | | - Thomas Taus
- Institut für Populationsgenetik, Vetmeduni Vienna, Austria.,Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Austria
| | - Viola Nolte
- Institut für Populationsgenetik, Vetmeduni Vienna, Austria
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Aggarwal DD, Rybnikov S, Cohen I, Frenkel Z, Rashkovetsky E, Michalak P, Korol AB. Desiccation-induced changes in recombination rate and crossover interference in Drosophila melanogaster: evidence for fitness-dependent plasticity. Genetica 2019; 147:291-302. [PMID: 31240599 DOI: 10.1007/s10709-019-00070-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 06/18/2019] [Indexed: 12/31/2022]
Abstract
Meiotic recombination is evolutionarily ambiguous, as being associated with both benefits and costs to its bearers, with the resultant dependent on a variety of conditions. While existing theoretical models explain the emergence and maintenance of recombination, some of its essential features remain underexplored. Here we focus on one such feature, recombination plasticity, and test whether recombination response to stress is fitness-dependent. We compare desiccation stress effects on recombination rate and crossover interference in chromosome 3 between desiccation-sensitive and desiccation-tolerant Drosophila lines. We show that relative to desiccation-tolerant genotypes, desiccation-sensitive genotypes exhibit a significant segment-specific increase in single- and double-crossover frequencies across the pericentromeric region of chromosome 3. Significant changes (relaxation) in crossover interference were found for the interval pairs flanking the centromere and extending to the left arm of the chromosome. These results indicate that desiccation is a recombinogenic factor and that desiccation-induced changes in both recombination rate and crossover interference are fitness-dependent, with a tendency of less fitted individuals to produce more variable progeny. Such dependence may play an important role in the regulation of genetic variation in populations experiencing environmental challenges.
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Affiliation(s)
- Dau Dayal Aggarwal
- Institute of Evolution, University of Haifa, 3498838, Haifa, Israel.,Department of Zoology, Banaras Hindu University, Varanasi, 221005, India
| | - Sviatoslav Rybnikov
- Institute of Evolution, University of Haifa, 3498838, Haifa, Israel.,Department of Evolutionary and Environmental Biology, University of Haifa, 3498838, Haifa, Israel
| | - Irit Cohen
- Institute of Evolution, University of Haifa, 3498838, Haifa, Israel.,Department of Evolutionary and Environmental Biology, University of Haifa, 3498838, Haifa, Israel
| | - Zeev Frenkel
- Department of Mathematics and Computational Science, Ariel University, 40700, Ariel, Israel
| | | | - Pawel Michalak
- Institute of Evolution, University of Haifa, 3498838, Haifa, Israel.,Edward Via College of Osteopathic Medicine, Blacksburg, VA, 24060, USA.,Center for One Health Research, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, 24060, USA
| | - Abraham B Korol
- Institute of Evolution, University of Haifa, 3498838, Haifa, Israel. .,Department of Evolutionary and Environmental Biology, University of Haifa, 3498838, Haifa, Israel.
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Singh ND. Wolbachia Infection Associated with Increased Recombination in Drosophila. G3 (BETHESDA, MD.) 2019; 9:229-237. [PMID: 30459180 PMCID: PMC6325905 DOI: 10.1534/g3.118.200827] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 11/18/2018] [Indexed: 12/14/2022]
Abstract
Wolbachia is a maternally-transmitted endosymbiotic bacteria that infects a large diversity of arthropod and nematode hosts. Some strains of Wolbachia are parasitic, manipulating host reproduction to benefit themselves, while other strains of Wolbachia exhibit obligate or facultative mutualisms with their host. The effects of Wolbachia on its host are many, though primarily relate to host immune and reproductive function. Here we test the hypothesis that Wolbachia infection alters the frequency of homologous recombination during meiosis. We use D. melanogaster as a model system, and survey recombination in eight wild-derived Wolbachia-infected (strain wMel) and Wolbachia-uninfected strains, controlling for genotype. We measure recombination in two intervals of the genome. Our results indicate that Wolbachia infection is associated with increased recombination in one genomic interval and not the other. The effect of Wolbachia infection on recombination is thus heterogenous across the genome. Our data also indicate a reproductive benefit of Wolbachia infection; infected females show higher fecundity than their uninfected genotypic controls. Given the prevalence of Wolbachia infection in natural populations, our findings suggest that Wolbachia infection is likely to contribute to recombination rate and fecundity variation among individuals in nature.
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Affiliation(s)
- Nadia D Singh
- Department of Biology, University of Oregon Eugene OR, 97403
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