scholarly journals Atypical meiosis can be adaptive in outcrossed S. pombe due to wtf meiotic drivers

2020 ◽  
Author(s):  
María Angélica Bravo Núñez ◽  
Ibrahim M. Sabbarini ◽  
Lauren E. Eide ◽  
Robert L. Unckless ◽  
Sarah E. Zanders
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fitness Landscape ◽  
Fitness Cost ◽  
Fitness Costs ◽  
Diploid Gametes ◽  
Selection Of

AbstractKiller meiotic drivers are genetic parasites that destroy ‘sibling’ gametes lacking the driver allele. The fitness costs of drive can lead to selection of unlinked suppressors. This suppression could involve evolutionary tradeoffs that compromise gametogenesis and contribute to infertility. Schizosaccharomyces pombe, an organism containing numerous gamete-killing wtf drivers, offers a tractable system to test this hypothesis. Here, we demonstrate that in scenarios analogous to outcrossing, wtf drivers generate a fitness landscape in which atypical gametes, such as aneuploids and diploids, are advantageous. In this context, wtf drivers can decrease the fitness cost of mutations that disrupt meiotic fidelity and, in some circumstances, can even make such mutations beneficial. Moreover, we find that S. pombe isolates vary greatly in their ability to make haploid gametes, with some isolates generating more than 25% aneuploid or diploid gametes. This work empirically demonstrates the potential for meiotic drivers to shape the evolution of gametogenesis.

scholarly journals Atypical meiosis can be adaptive in outcrossed Schizosaccharomyces pombe due to wtf meiotic drivers

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
María Angélica Bravo Núñez ◽  
Ibrahim M Sabbarini ◽  
Lauren E Eide ◽  
Robert L Unckless ◽  
Sarah E Zanders
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fitness Landscape ◽  
Fitness Costs ◽  
Spore Killing ◽  
Selection Of

Killer meiotic drivers are genetic parasites that destroy ‘sibling’ gametes lacking the driver allele. The fitness costs of drive can lead to selection of unlinked suppressors. This suppression could involve evolutionary tradeoffs that compromise gametogenesis and contribute to infertility. Schizosaccharomyces pombe, an organism containing numerous gamete (spore)-killing wtf drivers, offers a tractable system to test this hypothesis. Here, we demonstrate that in scenarios analogous to outcrossing, wtf drivers generate a fitness landscape in which atypical spores, such as aneuploids and diploids, are advantageous. In this context, wtf drivers can decrease the fitness costs of mutations that disrupt meiotic fidelity and, in some circumstances, can even make such mutations beneficial. Moreover, we find that S. pombe isolates vary greatly in their ability to make haploid spores, with some isolates generating up to 46% aneuploid or diploid spores. This work empirically demonstrates the potential for meiotic drivers to shape the evolution of gametogenesis.

scholarly journals In-vivo mutation rates and fitness landscape of HIV-1

2016 ◽  
Author(s):  
Fabio Zanini ◽  
Vadim Puller ◽  
Johanna Brodin ◽  
Jan Albert ◽  
Richard Neher
Keyword(s):  
Temporal Dynamics ◽  
Fitness Landscape ◽  
Large Fraction ◽  
Fitness Cost ◽  
Mutation Rates ◽  
Sequencing Data ◽  
Fitness Costs ◽  
Synonymous Mutations ◽  
Hiv 1

Mutation rates and fitness costs of deleterious mutations are difficult to measurein vivobut essential for a quantitative understanding of evolution. Using whole genome deep sequencing data from longitudinal samples during untreated HIV-1 infection, we estimated mutation rates and fitness costs in HIV-1 from the temporal dynamics of genetic variation. At approximately neutral sites, mutations accumulate with a rate of 1.2 x 10-5per site per day, in agreement with the rate measured in cell cultures. The rate from G to A is largest, followed by the other transitions C to T, T to C, and A to G, while transversions are more rare. At non-neutral sites, most mutations reduce virus replication; using a model of mutation selection balance, we estimated the fitness cost of mutations at every site in the HIV-1 genome. About half of all nonsynonymous mutations have large fitness costs (greater than 10%), while most synonymous mutations have costs below 1%. The cost of synonymous mutations is especially low in most of gag and pol, while much higher costs are observed in important RNA structures and regulatory regions. The intrapatient fitness cost estimates are consistent across multiple patients, suggesting that the deleterious part of the fitness landscape is universal and explains a large fraction of global HIV-1 group M diversity.

scholarly journals Fitness of Herbicide-Resistant Weeds: Current Knowledge and Implications for Management

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Management Practices ◽  
Current Knowledge ◽  
Resistance Management ◽  
Fitness Cost ◽  
Plant Fitness ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Wide Range

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.

scholarly journals Fitness Costs of Chlorantraniliprole Resistance Related to the SeNPF Overexpression in the Spodoptera exigua (Lepidoptera: Noctuidae)

2021 ◽  
Vol 22 (9) ◽  
pp. 5027
Author(s):  
Changwei Gong ◽  
Xinge Yao ◽  
Qunfang Yang ◽  
Xuegui Wang ◽  
Yuming Zhang ◽  
...  
Keyword(s):  
Insect Pest ◽  
Ryanodine Receptors ◽  
Oviposition Rate ◽  
Fitness Cost ◽  
Fitness Costs ◽  
Male Adult ◽  
Mating Response ◽  
Transmembrane Segments ◽  
High Level ◽  
Lepidoptera Noctuidae

Spodopteraexigua, a multifeeding insect pest, has developed a high level of resistance to chlorantraniliprole, which is a benzoylurea insecticide that targets the ryanodine receptors (RyRs). Herein, the resistant strain (SE-Sel) and sensitive strain (SE-Sus) were obtained by bidirectional screening for six generations. The potential oviposited eggs and oviposition rate of the SE-Sel strain were dramatically lower than those of the SE-Sus strain; on the contrary, the weights of prepupae and preadult were significantly increased. As a post-mating response, the higher number of non-oviposited eggs in the SE-Sel strain was caused by a lower mating rate. In addition, the expression levels of vitellogenin (SeVg) and its receptor (SeVgR) in the SE-Sel strain were consistently lower than those in the SE-Sus strain. An RyRI4743M mutation, contributing to the resistance to chlorantraniliprole, was located in the S3 transmembrane segments and might have affected the release of calcium ions; it led to the upregulated expression of the neuropeptide SeNPF and its receptor SeNPFR, and the mating and oviposition rate were significantly recovered when the SeNPF was knocked down though RNA interference (RNAi) in the male adult of the SE-Sel strain. Moreover, the expression of the juvenile hormone-binding proteins SeJHBWDS3 and SeJHBAN in the male adult of the SE-Sel strain was significantly decreased, which proved the existence of a fitness cost from another angle. Therefore, these results indicate that the fitness cost accompanied by chlorantraniliprole resistance in S. exigua may be related to the decrease in mating desire due to SeNPF overexpression.

Age-dependent fitness costs of alarm signaling in aphids

2003 ◽  
Vol 81 (5) ◽  
pp. 757-762 ◽  
Author(s):  
Edward B Mondor ◽  
Bernard D Roitberg
Keyword(s):  
Alarm Pheromone ◽  
Fourth Instar ◽  
Fitness Cost ◽  
Fitness Costs ◽  
Alarm Signal ◽  
Offspring Production ◽  
Direct Fitness ◽  
Alarm Signaling ◽  
Pea Aphids ◽  
Age Dependent

For an alarm signal to evolve, the benefits to the signaler must outweigh the costs of sending the signal. Research has largely focused on the benefits of alarm signaling, and the costs to an organism of sending an alarm signal are not well known. When attacked by a predator, aphids secrete cornicle droplets, containing an alarm pheromone, for individual protection and to warn clonemates. As aphid alarm pheromone is synthesized de novo in a feedback loop with juvenile hormone, we hypothesized that the secretion of cornicle droplets may result in a direct fitness cost to the emitter. We show that the secretion of a single cornicle droplet by pre-reproductive (third- and fourth-instar) pea aphids, Acyrthosiphon pisum, directly altered the timing and number of offspring produced. Third-instar pea aphids delayed offspring production but produced more offspring overall than non-secreting aphids, demonstrating a life-history shift but no significant fitness cost of droplet secretion. Fourth-instar pea aphids also delayed offspring production but produced the same number of offspring as non-secretors, resulting in a direct fitness cost of droplet secretion. Offspring production by adult, reproductive pea aphids that secreted a cornicle droplet did not differ from that of non-secretors. Thus, the fitness costs of secreting cornicle droplets containing an alarm signal are age-dependent.

scholarly journals Within-patient mutation frequencies reveal fitness costs of CpG dinucleotides and drastic amino acid changes in HIV

2016 ◽  
Author(s):  
Kristof Theys ◽  
Alison F. Feder ◽  
Maoz Gelbart ◽  
Marion Hartl ◽  
Adi Stern ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mutation Rate ◽  
Fitness Landscape ◽  
Fitness Costs ◽  
Nonsense Mutations ◽  
Cpg Dinucleotides ◽  
Synonymous Mutations ◽  
The Cost ◽  
Patient Mutation

AbstractHIV has a high mutation rate, which contributes to its ability to evolve quickly. However, we know little about the fitness costs of individual HIV mutationsin vivo, their distribution and the different factors shaping the viral fitness landscape. We calculated the mean frequency of transition mutations at 870 sites of thepolgene in 160 patients, allowing us to determine the cost of these mutations. As expected, we found high costs for non-synonymous and nonsense mutations as compared to synonymous mutations. In addition, we found that non-synonymous mutations that lead to drastic amino acid changes are twice as costly as those that do not and mutations that create new CpG dinucleotides are also twice as costly as those that do not. We also found that G→A and C→T mutations are more costly than A→G mutations. We anticipate that our newin vivofrequency-based approach will provide insights into the fitness landscape and evolvability of not only HIV, but a variety of microbes.Author summaryHIV’s high mutation rate allows it to evolve quickly. However, most mutations probably reduce the virus’ ability to replicate – they are costly to the virus. Until now, the actual cost of mutations is not well understood. We used within-patient mutation frequencies to estimate the cost of 870 HIV mutationsin vivo. As expected, we found high costs for non-synonymous and nonsense mutations. In addition, we found surprisingly high costs for mutations that lead to drastic amino acid changes, mutations that create new CpG sites (possibly because they trigger the host’s immune system), and G→A and C→T mutations. Our results demonstrate the power of analyzing mutant frequencies fromin vivoviral populations to study costs of mutations. A better understanding of fitness costs will help to predict the evolution of HIV.

scholarly journals Adaptive Approaches Towards Better GA Performance in Dynamic Fitness Landscapes

1994 ◽  
Vol 23 (487) ◽  
Author(s):  
Henrik Hautop Lund
Keyword(s):  
Fitness Landscape ◽  
Dynamic Environments ◽  
Mutation Rates ◽  
Landscape Changes ◽  
Correlation Measure ◽  
The Right ◽  
Changes Over Time ◽  
Adaptive Approaches ◽  
Over Time ◽  
Selection Of

We review different techniques for improving GA performance. By analysing the fitness landscape, a correlation measure between parents and offspring can be provided, and we can estimate effectively which genetic operator to use in the GA for a given fitness landscape. The response to selection equation further tells us how well the GA will do, and combining the two approaches gives us a powerful tool to automatically ensure the selection of the right parameter settings for a given problem. In dynamic environments the fitness landscape changes over time, and the evolved systems should be able to adapt to such changes. By introducing evolvable mutation rates and evolvable fitness formulae, we obtain such systems. The systems are shown to be able to adapt to both internal and external constraints and changes.

scholarly journals Fitness selection of hyperfusogenic measles virus F proteins associated with neuropathogenic phenotypes

2021 ◽  
Vol 118 (18) ◽  
pp. e2026027118
Author(s):  
Satoshi Ikegame ◽  
Takao Hashiguchi ◽  
Chuan-Tien Hung ◽  
Kristina Dobrindt ◽  
Kristen J. Brennand ◽  
...  
Keyword(s):  
Measles Virus ◽  
Fitness Landscape ◽  
Subacute Sclerosing Panencephalitis ◽  
Brain Regions ◽  
Wild Type ◽  
Genomic Context ◽  
Fitness Advantage ◽  
Human Neurons ◽  
Selection Of

Measles virus (MeV) is resurgent and caused >200,000 deaths in 2019. MeV infection can establish a chronic latent infection of the brain that can recrudesce months to years after recovery from the primary infection. Recrudescent MeV leads to fatal subacute sclerosing panencephalitis (SSPE) or measles inclusion body encephalitis (MIBE) as the virus spreads across multiple brain regions. Most clinical isolates of SSPE/MIBE strains show mutations in the fusion (F) gene that result in a hyperfusogenic phenotype in vitro and allow for efficient spread in primary human neurons. Wild-type MeV receptor-binding protein is indispensable for manifesting these mutant F phenotypes, even though neurons lack canonical MeV receptors (CD150/SLAMF1 or nectin-4). How such hyperfusogenic F mutants are selected and whether they confer a fitness advantage for efficient neuronal spread is unresolved. To better understand the fitness landscape that allows for the selection of such hyperfusogenic F mutants, we conducted a screen of ≥3.1 × 105 MeV-F point mutants in their genomic context. We rescued and amplified our genomic MeV-F mutant libraries in BSR-T7 cells under conditions in which MeV-F-T461I (a known SSPE mutant), but not wild-type MeV, can spread. We recovered known SSPE mutants but also characterized at least 15 hyperfusogenic F mutations with an SSPE phenotype. Structural mapping of these mutants onto the prefusion MeV-F trimer confirm and extend our understanding of the F regulatory domains in MeV-F. Our list of hyperfusogenic F mutants is a valuable resource for future studies into MeV neuropathogenesis and the regulation of paramyxovirus F.

scholarly journals Sexual harassment induces a temporary fitness cost but does not constrain the acquisition of environmental information in fruit flies

2016 ◽  
Vol 12 (1) ◽  
pp. 20150917 ◽  
Author(s):  
Serafino Teseo ◽  
Liisa Veerus ◽  
Céline Moreno ◽  
Frédéric Mery
Keyword(s):  
Sexual Harassment ◽  
Social Contexts ◽  
Fruit Flies ◽  
Environmental Information ◽  
Learning Processes ◽  
Fitness Cost ◽  
Fitness Costs ◽  
Sexual Conflicts ◽  
Fitness Benefits ◽  
The Relationship

Across animals, sexual harassment induces fitness costs for females and males. However, little is known about the cognitive costs involved, i.e. whether it constrains learning processes, which could ultimately affect an individual's fitness. Here we evaluate the acquisition of environmental information in groups of fruit flies challenged with various levels of male sexual harassment. We show that, although high sexual harassment induces a temporary fitness cost for females, all fly groups of both sexes exhibit similar levels of learning. This suggests that, in fruit flies, the fitness benefits of acquiring environmental information are not affected by the fitness costs of sexual harassment, and that selection may favour cognition even in unfavourable social contexts. Our study provides novel insights into the relationship between sexual conflicts and cognition and the evolution of female counterstrategies against male sexual harassment.

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