Evolution Letters最新文献

{"title":"Parental care shapes the evolution of molecular genetic variation","authors":"Rahia Mashoodh, Angela T Trowsdale, Andrea Manica, Rebecca M Kilner","doi":"10.1093/evlett/qrad039","DOIUrl":"https://doi.org/10.1093/evlett/qrad039","url":null,"abstract":"Abstract Cooperative social behaviors, such as parental care, have long been hypothesized to relax selection leading to the accumulation of genetic variation in populations. Although the idea has been discussed for decades, there has been relatively little experimental work to investigate how social behavior contributes to genetic variation in populations. Here, we investigate how parental care can shape molecular genetic variation in the subsocial insect, Nicrophorus vespilloides. Using whole-genome sequencing of populations that had evolved in the presence or absence of parental care for 30 generations, we show that parental care maintains levels of standing genetic variation. In contrast, under a harsh environment without care, strong directional selection caused a reduction in genetic variation. Furthermore, we show that adaptation to the loss of care is associated with genetic divergence between populations at loci related to stress, morphological development, and transcriptional regulation. These data reveal how social behavior is linked to the genetic processes that shape and maintain genetic diversity within populations, and provides rare empirical evidence for an old hypothesis.","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135254503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High parasite virulence necessary for the maintenance of host outcrossing via parasite-mediated selection","authors":"Samuel P Slowinski, JaeHoon Cho, McKenna J Penley, Laura W Alexander, Arielle B Greenberg, Sathvik R Namburar, Levi T Morran","doi":"10.1093/evlett/qrad036","DOIUrl":"https://doi.org/10.1093/evlett/qrad036","url":null,"abstract":"Abstract Biparental sex is widespread in nature, yet costly relative to uniparental reproduction. It is generally unclear why self-fertilizing or asexual lineages do not readily invade outcrossing populations. The Red Queen hypothesis predicts that coevolving parasites can prevent self-fertilizing or asexual lineages from invading outcrossing host populations. However, only highly virulent parasites are predicted to maintain outcrossing, which may limit the general applicability of the Red Queen hypothesis. Here, we tested whether the ability of coevolving parasites to prevent invasion of self-fertilization within outcrossing host populations was dependent on parasite virulence. We introduced wild-type Caenorhabditis elegans hermaphrodites, capable of both self-fertilization and outcrossing, into C. elegans populations fixed for a mutant allele conferring obligate outcrossing. Replicate C. elegans populations were exposed for 24 host generations to one of four strains of Serratia marcescens parasites that varied in virulence, under three treatments: a heat-killed (control, noninfectious) parasite treatment, a fixed-genotype (nonevolving) parasite treatment, and a copassaged (potentially coevolving) parasite treatment. As predicted, self-fertilization invaded C. elegans host populations in the control and fixed-parasite treatments, regardless of parasite virulence. In the copassaged treatment, selfing invaded host populations coevolving with low- to mid-virulence strains, but remained rare in hosts coevolving with highly virulent bacterial strains. Therefore, we found that only highly virulent coevolving parasites can impede the invasion of selfing.","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135254277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasticity and the adaptive evolution of switchlike reaction norms under environmental change","authors":"Claudia Crowther, Stephen P Bonser, Lisa E Schwanz","doi":"10.1093/evlett/qrad035","DOIUrl":"https://doi.org/10.1093/evlett/qrad035","url":null,"abstract":"Abstract Phenotypic plasticity is often posited as an avenue for adaptation to environmental change, whereby environmental influences on phenotypes could shift trait expression toward new optimal values. Conversely, plastic trait expression may inhibit adaptation to environmental change by reducing selective pressure on ill-adapted traits. While plastic responses are often assumed to be linear, nonlinear phenotype–environment relationships are common, especially in thermally sensitive traits. Here we examine nonlinear plasticity in a trait with great ecological and evolutionary significance: sexual phenotype in species with environmental sex determination (ESD). In species with ESD, development switches between male and female at an environmental threshold (the inflection point). The inflection point is a key trait for adaptive responses to changing environments and should evolve toward the new optimum in order to maintain evolutionarily stable sex ratios. We used an individual-based theoretical model to investigate how two forms of plasticity in the ESD reaction norm—the nonlinear slope of the reaction norm and a linear shift in the inflection point—influence the evolution of the inflection point under climate warming. We found that steeper reaction norm slopes (high nonlinear plasticity) promoted evolution toward new optimal phenotypes (higher inflection points). In contrast, increased linear plasticity in the inflection point (shift) hindered adaptive evolution. Additionally, populations in moderate warming scenarios showed greater adaptive evolution of the inflection point compared with populations in extreme warming scenarios, suggesting that the proximity of existing phenotypes to new optimal phenotypes influences evolutionary outcomes. Unexpectedly, we found greater population persistence under high climate variability, due to the increased production of rare-sex individuals in unusually cold years. Our results demonstrate that different forms of phenotypic plasticity have crucially different effects on adaptive evolution. Plasticity that prevented sex ratio bias hindered the evolution of the inflection point, while plasticity that exacerbated sex ratio bias promoted adaptation to environmental change.","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135890508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical transmission does not always lead to benign pathogen-host associations.","authors":"George Shillcock,&nbsp;Francisco Úbeda,&nbsp;Geoff Wild","doi":"10.1093/evlett/qrad028","DOIUrl":"10.1093/evlett/qrad028","url":null,"abstract":"<p><p>Understanding the capacity of pathogens to cause severe disease is of fundamental importance to human health and the preservation of biodiversity. Many of those pathogens are not only transmitted horizontally between unrelated hosts but also vertically between parents and their progeny. It is widely accepted that vertical transmission leads to the evolution of less virulent pathogens, but this idea stems from research that neglects the evolutionary response of hosts. Here, we use a game-theory model of coevolution between pathogen and host to show that vertical transmission does not always lead to more benign pathogens. We highlight scenarios in which vertical transmission results in pathogens exhibiting more virulence. However, we also predict that more benign outcomes are still possible (a) when generating new horizontal infections inflicts too much damage on hosts, (b) when clearing an infection is too costly for the host, and (c) when vertical transmission is promoted by a greater growth rate of the host population. Though our work offers a new perspective on the role of vertical transmission in pathogen-host systems, it does agree with previous experimental work.</p>","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"7 5","pages":"305-314"},"PeriodicalIF":5.0,"publicationDate":"2023-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10565904/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41216638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of seminal fluid gene expression on paternity.","authors":"Leigh W Simmons, Maxine Lovegrove","doi":"10.1093/evlett/qrad033","DOIUrl":"10.1093/evlett/qrad033","url":null,"abstract":"<p><p>When females mate with more than one male, competition between rival ejaculates is expected to favor adaptations that promote fertilization success. There is now compelling evidence that sperm competition selects for increased production and allocation of sperm. However, sperm comes packaged in ejaculates that also contain protein-rich seminal fluids. Predicting how males should allocate individual seminal fluid proteins in response to sperm competition is hampered by our limited knowledge of their precise function. We use gene expression studies and interference RNA to ask how seminal fluid proteins in the ejaculate of a cricket, <i>Teleogryllus oceanicus</i>, affect a male's paternity share when in competition for fertilizations. We find that the relative expression of one seminal fluid gene, <i>gagein</i>, positively affects the paternity share of competing males and that knockdown of this and two other seminal fluid protein genes renders males mating in the offensive role of sperm competition incapable of fathering living offspring. Despite having a negative effect on offspring viability these seminal fluid genes have been found to be up regulated in response to rival males, consistent with a role in promoting competitive fertilization success. Our data contribute to a growing body of evidence that, like sperm, seminal fluid gene expression is subject to post-mating sexual selection via sperm competition.</p>","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"7 5","pages":"361-369"},"PeriodicalIF":3.4,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10565890/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41216637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolutionary barriers to horizontal gene transfer in macrophage-associated <i>Salmonella</i>.","authors":"Rama P Bhatia,&nbsp;Hande Acar Kirit,&nbsp;Cecil M Lewis,&nbsp;Krithivasan Sankaranarayanan,&nbsp;Jonathan P Bollback","doi":"10.1093/evlett/qrad020","DOIUrl":"https://doi.org/10.1093/evlett/qrad020","url":null,"abstract":"<p><p>Horizontal gene transfer (HGT) is a powerful evolutionary force facilitating bacterial adaptation and emergence of novel phenotypes. Several factors, including environmental ones, are predicted to restrict HGT, but we lack systematic and experimental data supporting these predictions. Here, we address this gap by measuring the relative fitness of 44 genes horizontally transferred from <i>Escherichia coli</i> to <i>Salmonella enterica</i> in infection-relevant environments. We estimated the distribution of fitness effects in each environment and identified that dosage-dependent effects across different environments are a significant barrier to HGT. The majority of genes were found to be deleterious. We also found longer genes had stronger negative fitness consequences than shorter ones, showing that gene length was negatively associated with HGT. Furthermore, fitness effects of transferred genes were found to be environmentally dependent. In summary, a substantial fraction of transferred genes had a significant fitness cost on the recipient, with both gene characteristics and the environment acting as evolutionary barriers to HGT.</p>","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"7 4","pages":"227-239"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10355182/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10226510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coprophagy rapidly matures juvenile gut microbiota in a precocial bird.","authors":"Elin Videvall,&nbsp;Hanna M Bensch,&nbsp;Anel Engelbrecht,&nbsp;Schalk Cloete,&nbsp;Charlie K Cornwallis","doi":"10.1093/evlett/qrad021","DOIUrl":"https://doi.org/10.1093/evlett/qrad021","url":null,"abstract":"<p><p>Coprophagy is a behavior where animals consume feces, and has been observed across a wide range of species, including birds and mammals. The phenomenon is particularly prevalent in juveniles, but the reasons for this remain unclear. One hypothesis is that coprophagy enables offspring to acquire beneficial gut microbes that aid development. However, despite the potential importance of this behavior, studies investigating the effects in juveniles are rare. Here we experimentally test this idea by examining how ingestion of adult feces by ostrich chicks affects their gut microbiota development, growth, feeding behavior, pathogen abundance, and mortality. We conducted extensive longitudinal experiments for 8 weeks, repeated over 2 years. It involved 240 chicks, of which 128 were provided daily access to fresh fecal material from adults and 112 were simultaneously given a control treatment. Repeated measures, behavioral observations, and DNA metabarcoding of the microbial gut community, both prior to and over the course of the experiment, allowed us to evaluate multiple aspects of the behavior. The results show that coprophagy causes (a) marked shifts to the juvenile gut microbiota, including a major increase in diversity and rapid maturation of the microbial composition, (b) higher growth rates (fecal-supplemented chicks became 9.4% heavier at 8 weeks old), (c) changes to overall feeding behavior but no differences in feed intake, (d) lower abundance of a common gut pathogen (<i>Clostridium colinum</i>), and (e) lower mortality associated with gut disease. Together, our results suggest that the behavior of coprophagy in juveniles is highly beneficial and may have evolved to accelerate the development of gut microbiota.</p>","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"7 4","pages":"240-251"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/e9/ce/qrad021.PMC10355177.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10207790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental estimates of germline mutation rate in eukaryotes: a phylogenetic meta-analysis.","authors":"Yiguan Wang,&nbsp;Darren J Obbard","doi":"10.1093/evlett/qrad027","DOIUrl":"https://doi.org/10.1093/evlett/qrad027","url":null,"abstract":"<p><p>Mutation is the ultimate source of all genetic variation, and over the last 10 years the ready availability of whole-genome sequencing has permitted direct estimation of mutation rate for many non-model species across the tree of life. In this meta-analysis, we make a comprehensive search of the literature for mutation rate estimates in eukaryotes, identifying 140 mutation accumulation (MA) and parent-offspring (PO) sequencing studies covering 134 species. Based on these data, we revisit differences in the single-nucleotide mutation (SNM) rate between different phylogenetic lineages and update the known relationships between mutation rate and generation time, genome size, and nucleotide diversity-while accounting for phylogenetic nonindependence. We do not find a significant difference between MA and PO in estimated mutation rates, but we confirm that mammal and plant lineages have higher mutation rates than arthropods and that unicellular eukaryotes have the lowest mutation rates. We find that mutation rates are higher in species with longer generation times and larger genome sizes, even when accounting for phylogenetic relationships. Moreover, although nucleotide diversity is positively correlated with mutation rate, the gradient of the relationship is significantly less than one (on a logarithmic scale), consistent with higher mutation rates in populations with smaller effective size. For the 29 species for which data are available, we find that indel mutation rates are positively correlated with nucleotide mutation rates and that short deletions are generally more common than short insertions. Nevertheless, despite recent progress, no estimates of either SNM or indel mutation rates are available for the majority of deeply branching eukaryotic lineages-or even for most animal phyla. Even among charismatic megafauna, experimental mutation rate estimates remain unknown for amphibia and scarce for reptiles and fish.</p>","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"7 4","pages":"216-226"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/d1/b9/qrad027.PMC10355183.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10208250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The coevolutionary dynamics of cryptic female choice.","authors":"Matthew C Kustra,&nbsp;Suzanne H Alonzo","doi":"10.1093/evlett/qrad025","DOIUrl":"https://doi.org/10.1093/evlett/qrad025","url":null,"abstract":"<p><p>In contrast to sexual selection on traits that affect interactions between the sexes before mating, little theoretical research has focused on the coevolution of postmating traits via cryptic female choice (when females bias fertilization toward specific males). We used simulation models to ask (a) whether and, if so, how nondirectional cryptic female choice (female-by-male interactions in fertilization success) causes deviations from models that focus exclusively on male-mediated postmating processes, and (b) how the risk of sperm competition, the strength of cryptic female choice, and tradeoffs between sperm number and sperm traits interact to influence the coevolutionary dynamics between cryptic female choice and sperm traits. We found that incorporating cryptic female choice can result in males investing much less in their ejaculates than predicted by models with sperm competition only. We also found that cryptic female choice resulted in the evolution of genetic correlations between cryptic female choice and sperm traits, even when the strength of cryptic female choice was weak, and the risk of sperm competition was low. This suggests that cryptic female choice may be important even in systems with low multiple mating. These genetic correlations increased with the risk of sperm competition and as the strength of cryptic female choice increased. When the strength of cryptic female choice and risk of sperm competition was high, extreme codivergence of sperm traits and cryptic female choice preference occurred even when the sperm trait traded off with sperm number. We also found that male traits lagged behind the evolution of female traits; this lag decreased with increasing strength of cryptic female choice and risk of sperm competition. Overall, our results suggest that cryptic female choice deserves more attention theoretically and may be driving trait evolution in ways just beginning to be explored.</p>","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"7 4","pages":"191-202"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10355280/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10239567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hypermutator emergence in experimental <i>Escherichia coli</i> populations is stress-type dependent.","authors":"Martijn Callens,&nbsp;Caroline J Rose,&nbsp;Michael Finnegan,&nbsp;François Gatchitch,&nbsp;Léna Simon,&nbsp;Jeanne Hamet,&nbsp;Léa Pradier,&nbsp;Marie-Pierre Dubois,&nbsp;Stéphanie Bedhomme","doi":"10.1093/evlett/qrad019","DOIUrl":"https://doi.org/10.1093/evlett/qrad019","url":null,"abstract":"<p><p>Genotypes exhibiting an increased mutation rate, called hypermutators, can propagate in microbial populations because they can have an advantage due to the higher supply of beneficial mutations needed for adaptation. Although this is a frequently observed phenomenon in natural and laboratory populations, little is known about the influence of parameters such as the degree of maladaptation, stress intensity, and the genetic architecture for adaptation on the emergence of hypermutators. To address this knowledge gap, we measured the emergence of hypermutators over ~1,000 generations in experimental <i>Escherichia coli</i> populations exposed to different levels of osmotic or antibiotic stress. Our stress types were chosen based on the assumption that the genetic architecture for adaptation differs between them. Indeed, we show that the size of the genetic basis for adaptation is larger for osmotic stress compared to antibiotic stress. During our experiment, we observed an increased emergence of hypermutators in populations exposed to osmotic stress but not in those exposed to antibiotic stress, indicating that hypermutator emergence rates are stress type dependent. These results support our hypothesis that hypermutator emergence is linked to the size of the genetic basis for adaptation. In addition, we identified other parameters that covaried with stress type (stress level and IS transposition rates) that might have contributed to an increased hypermutator provision and selection. Our results provide a first comparison of hypermutator emergence rates under varying stress conditions and point towards complex interactions of multiple stress-related factors on the evolution of mutation rates.</p>","PeriodicalId":48629,"journal":{"name":"Evolution Letters","volume":"7 4","pages":"252-261"},"PeriodicalIF":5.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/e4/3e/qrad019.PMC10355175.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10208249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}