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Orr SE, Hedrick NA, Murray KA, Pasupuleti AK, Kovacs JL, Goodisman MAD. Genetic and environmental effects on morphological traits of social phenotypes in wasps. Heredity (Edinb) 2024; 133:126-136. [PMID: 38918612 DOI: 10.1038/s41437-024-00701-5] [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: 09/27/2023] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
Many species exhibit distinct phenotypic classes, such as sexes in dioecious species or castes in social species. The evolution of these classes is affected by the genetic architecture governing traits shared between phenotypes. However, estimates of the genetic and environmental factors contributing to phenotypic variation in distinct classes have rarely been examined. We studied the genetic architecture underlying morphological traits in phenotypic classes in the social wasp Vespula maculifrons. Our data revealed patriline effects on a few traits, indicating weak genetic influences on caste phenotypic variation. Interestingly, traits exhibited higher heritability in queens than workers. This result suggests that genetic variation has a stronger influence on trait variation in the queen caste than the worker caste, which is unexpected because queens typically experience direct selection. Moreover, estimates of heritability for traits were correlated between the castes, indicating that variability in trait size was governed by similar genetic architecture in the two castes. However, we failed to find evidence for a significant relationship between caste dimorphism and caste correlation, as would be expected if trait evolution was constrained by intralocus genetic conflict. Our analyses also uncovered variation in the allometric relationships for traits. These analyses suggested that worker traits were proportionally smaller than queen traits for most traits examined. Overall, our data provide evidence for a strong environmental and moderate genetic basis of trait variation among castes. Moreover, our results suggest that selection previously operated on caste phenotype in this species, and phenotypic variation is now governed primarily by environmental differences.
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Affiliation(s)
- Sarah E Orr
- Georgia Institute of Technology, School of Biological Sciences, 310 Ferst Drive, Atlanta, 30318, Georgia
| | - Nicole A Hedrick
- Georgia Institute of Technology, School of Biological Sciences, 310 Ferst Drive, Atlanta, 30318, Georgia
| | - Kayla A Murray
- Georgia Institute of Technology, School of Biological Sciences, 310 Ferst Drive, Atlanta, 30318, Georgia
| | - Abhinav K Pasupuleti
- Georgia Institute of Technology, School of Biological Sciences, 310 Ferst Drive, Atlanta, 30318, Georgia
| | - Jennifer L Kovacs
- Georgia Institute of Technology, School of Biological Sciences, 310 Ferst Drive, Atlanta, 30318, Georgia
- Agnes Scott College, Department of Biology, 141 East College Avenue, Decatur, 30030, Georgia
| | - Michael A D Goodisman
- Georgia Institute of Technology, School of Biological Sciences, 310 Ferst Drive, Atlanta, 30318, Georgia.
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2
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Minovic A, Nozawa M. Evolution of sex-biased genes in Drosophila species with neo-sex chromosomes: Potential contribution to reducing the sexual conflict. Ecol Evol 2024; 14:e11701. [PMID: 39050657 PMCID: PMC11266434 DOI: 10.1002/ece3.11701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 06/17/2024] [Accepted: 06/21/2024] [Indexed: 07/27/2024] Open
Abstract
An advantage of sex chromosomes may be the potential to reduce sexual conflict because they provide a basis for selection to operate separately on females and males. However, evaluating the relationship between sex chromosomes and sexual conflict is challenging owing to the difficulty in measuring sexual conflict and substantial divergence between species with and without sex chromosomes. We therefore examined sex-biased gene expression as a proxy for sexual conflict in three sets of Drosophila species with and without young sex chromosomes, the so-called neo-sex chromosomes. In all sets, we detected more sex-biased genes in the species with neo-sex chromosomes than in the species without neo-sex chromosomes in larvae, pupae, and adult somatic tissues but not in gonads. In particular, many unbiased genes became either female- or male-biased after linkage to the neo-sex chromosomes in larvae, despite the low sexual dimorphism. For example, genes involved in metabolism, a key determinant for the rate of development in many animals, were enriched in the genes that acquired sex-biased expression on the neo-sex chromosomes at the larval stage. These genes may be targets of sexually antagonistic selection (i.e., large size and rapid development are selected for in females but selected against in males). These results indicate that acquiring neo-sex chromosomes may have contributed to a reduction in sexual conflict, particularly at the larval stage, in Drosophila..
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Affiliation(s)
- Anika Minovic
- Department of Biological SciencesTokyo Metropolitan UniversityHachiojiJapan
| | - Masafumi Nozawa
- Department of Biological SciencesTokyo Metropolitan UniversityHachiojiJapan
- Research Center for Genomics and BioinformaticsTokyo Metropolitan UniversityHachiojiJapan
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3
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VanKuren NW, Chen J, Long M. Sexual conflict drive in the rapid evolution of new gametogenesis genes. Semin Cell Dev Biol 2024; 159-160:27-37. [PMID: 38309142 DOI: 10.1016/j.semcdb.2024.01.005] [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: 09/21/2023] [Revised: 01/19/2024] [Accepted: 01/19/2024] [Indexed: 02/05/2024]
Abstract
The evolutionary forces underlying the rapid evolution in sequences and functions of new genes remain a mystery. Adaptation by natural selection explains the evolution of some new genes. However, many new genes perform sex-biased functions that have rapidly evolved over short evolutionary time scales, suggesting that new gene evolution may often be driven by conflicting selective pressures on males and females. It is well established that such sexual conflict (SC) plays a central role in maintaining phenotypic and genetic variation within populations, but the role of SC in driving new gene evolution remains essentially unknown. This review explores the connections between SC and new gene evolution through discussions of the concept of SC, the phenotypic and genetic signatures of SC in evolving populations, and the molecular mechanisms by which SC could drive the evolution of new genes. We synthesize recent work in this area with a discussion of the case of Apollo and Artemis, two extremely young genes (<200,000 years) in Drosophila melanogaster, which offered the first empirical insights into the evolutionary process by which SC could drive the evolution of new genes. These new duplicate genes exhibit the hallmarks of sexually antagonistic selection: rapid DNA and protein sequence evolution, essential sex-specific functions in gametogenesis, and complementary sex-biased expression patterns. Importantly, Apollo is essential for male fitness but detrimental to female fitness, while Artemis is essential for female fitness but detrimental to male fitness. These sexually antagonistic fitness effects and complementary changes to expression, sequence, and function suggest that these duplicates were selected for mitigating SC, but that SC has not been fully resolved. Finally, we propose Sexual Conflict Drive as a self-driven model to interpret the rapid evolution of new genes, explain the potential for SC and sexually antagonistic selection to contribute to long-term evolution, and suggest its utility for understanding the rapid evolution of new genes in gametogenesis.
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Affiliation(s)
- Nicholas W VanKuren
- Department of Ecology and Evolution, The University of Chicago, United States.
| | - Jianhai Chen
- Department of Ecology and Evolution, The University of Chicago, United States
| | - Manyuan Long
- Department of Ecology and Evolution, The University of Chicago, United States.
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4
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Castellanos MDP, Wickramasinghe CD, Betrán E. The roles of gene duplications in the dynamics of evolutionary conflicts. Proc Biol Sci 2024; 291:20240555. [PMID: 38865605 DOI: 10.1098/rspb.2024.0555] [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: 08/08/2023] [Accepted: 04/02/2024] [Indexed: 06/14/2024] Open
Abstract
Evolutionary conflicts occur when there is antagonistic selection between different individuals of the same or different species, life stages or between levels of biological organization. Remarkably, conflicts can occur within species or within genomes. In the dynamics of evolutionary conflicts, gene duplications can play a major role because they can bring very specific changes to the genome: changes in protein dose, the generation of novel paralogues with different functions or expression patterns or the evolution of small antisense RNAs. As we describe here, by having those effects, gene duplication might spark evolutionary conflict or fuel arms race dynamics that takes place during conflicts. Interestingly, gene duplication can also contribute to the resolution of a within-locus evolutionary conflict by partitioning the functions of the gene that is under an evolutionary trade-off. In this review, we focus on intraspecific conflicts, including sexual conflict and illustrate the various roles of gene duplications with a compilation of examples. These examples reveal the level of complexity and the differences in the patterns of gene duplications within genomes under different conflicts. These examples also reveal the gene ontologies involved in conflict and the genomic location of the elements of the conflict. The examples provide a blueprint for the direct study of these conflicts or the exploration of the presence of similar conflicts in other lineages.
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Affiliation(s)
| | | | - Esther Betrán
- Department of Biology, University of Texas at Arlington , Arlington, TX 76019, USA
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5
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Bravo C, Bautista-Sopelana LM, Alonso JC. Revisiting niche divergence hypothesis in sexually dimorphic birds: Is diet overlap correlated with sexual size dimorphism? J Anim Ecol 2024; 93:460-474. [PMID: 38462717 DOI: 10.1111/1365-2656.14058] [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: 01/23/2023] [Accepted: 01/04/2024] [Indexed: 03/12/2024]
Abstract
The evolution of sexual size dimorphism (SSD) is a long-standing topic in evolutionary biology, but there is little agreement on the extent to which SSD is driven by the different selective forces. While sexual selection and fecundity selection have traditionally been proposed as the two leading hypotheses, SSD may also result from natural selection through mechanisms such as sexual niche divergence, which might have reduced resource competition between sexes. Here, we revisited the niche divergence hypothesis by testing the relationship between the sexual overlap in diet and SSD of 56 bird species using phylogenetic comparative analyses. We then assessed how SSD variation relates to the three main hypotheses: sexual selection, fecundity selection, and sexual niche divergence using phylogenetic generalized least squares (PGLS). Then, we compared sexual selection, fecundity selection and niche divergence selection as SSD drivers through phylogenetic confirmatory path analyses to disentangle the possible causal evolutionary relationships between SSD and the three hypotheses. Phylogenetic generalized least squares showed that SSD was negatively correlated with diet overlap, that is, the greater the difference in body size between males and females, the less diet overlap. As predicted by sexual selection theory, the difference in body size between sexes was higher in polygynous species. Confirmatory phylogenetic path analyses suggested that the most likely evolutionary path might include the mating system as a main driver in SSD and niche divergence as a result of SSD. We found no evidence of a role of fecundity selection in the evolution of female-biased SSD. Our study provides evidence that sexual selection has likely been the main cause of SSD and that dietary divergence is likely an indirect effect of SSD.
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Affiliation(s)
- Carolina Bravo
- Instituto de Investigación en Recursos Cinegéticos (IREC)-(CSIC-UCLM-JCCM), Ciudad Real, Spain
| | | | - Juan Carlos Alonso
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (MNCN), CSIC, Madrid, Spain
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Alton LA, Kutz T, Bywater CL, Lombardi E, Cockerell FE, Layh S, Winwood-Smith H, Arnold PA, Beaman JE, Walter GM, Monro K, Mirth CK, Sgrò CM, White CR. Temperature and nutrition do not interact to shape the evolution of metabolic rate. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220484. [PMID: 38186272 PMCID: PMC10772606 DOI: 10.1098/rstb.2022.0484] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/22/2023] [Indexed: 01/09/2024] Open
Abstract
Metabolic cold adaptation, or Krogh's rule, is the controversial hypothesis that predicts a monotonically negative relationship between metabolic rate and environmental temperature for ectotherms living along thermal clines measured at a common temperature. Macrophysiological patterns consistent with Krogh's rule are not always evident in nature, and experimentally evolved responses to temperature have failed to replicate such patterns. Hence, temperature may not be the sole driver of observed variation in metabolic rate. We tested the hypothesis that temperature, as a driver of energy demand, interacts with nutrition, a driver of energy supply, to shape the evolution of metabolic rate to produce a pattern resembling Krogh's rule. To do this, we evolved replicate lines of Drosophila melanogaster at 18, 25 or 28°C on control, low-calorie or low-protein diets. Contrary to our prediction, we observed no effect of nutrition, alone or interacting with temperature, on adult female and male metabolic rates. Moreover, support for Krogh's rule was only in females at lower temperatures. We, therefore, hypothesize that observed variation in metabolic rate along environmental clines arises from the metabolic consequences of environment-specific life-history optimization, rather than because of the direct effect of temperature on metabolic rate. This article is part of the theme issue 'The evolutionary significance of variation in metabolic rates'.
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Affiliation(s)
- Lesley A. Alton
- Centre for Geometric Biology, Monash University, Melbourne, Victoria 3800, Australia
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Teresa Kutz
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Candice L. Bywater
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Emily Lombardi
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Fiona E. Cockerell
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Sean Layh
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Hugh Winwood-Smith
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Pieter A. Arnold
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Julian E. Beaman
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Greg M. Walter
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Keyne Monro
- Centre for Geometric Biology, Monash University, Melbourne, Victoria 3800, Australia
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Christen K. Mirth
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Carla M. Sgrò
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Craig R. White
- Centre for Geometric Biology, Monash University, Melbourne, Victoria 3800, Australia
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
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7
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Ryu T, Okamoto K, Ansai S, Nakao M, Kumar A, Iguchi T, Ogino Y. Gene Duplication of Androgen Receptor As An Evolutionary Driving Force Underlying the Diversity of Sexual Characteristics in Teleost Fishes. Zoolog Sci 2024; 41:68-76. [PMID: 38587519 DOI: 10.2108/zs230098] [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: 10/06/2023] [Accepted: 01/15/2024] [Indexed: 04/09/2024]
Abstract
Sexual dimorphism allows species to meet their fitness optima based on the physiological availability of each sex. Although intralocus sexual conflict appears to be a genetic constraint for the evolution of sex-specific traits, sex-linked genes and the regulation of sex steroid hormones contribute to resolving this conflict by allowing sex-specific developments. Androgens and their receptor, androgen receptor (Ar), regulate male-biased phenotypes. In teleost fish, ar ohnologs have emerged as a result of teleost-specific whole genome duplication (TSGD). Recent studies have highlighted the evolutionary differentiation of ar ohnologs responsible for the development of sexual characteristics, which sheds light on the need for comparative studies on androgen regulation among different species. In this review, we discuss the importance of ar signaling as a regulator of male-specific traits in teleost species because teleost species are suitable experimental models for comparative studies owing to their great diversity in male-biased morphological and physiological traits. To date, both in vivo and in vitro studies on teleost ar ohnologs have shown a substantial influence of ars as a regulator of male-specific reproductive traits such as fin elongation, courtship behavior, and nuptial coloration. In addition to these sexual characteristics, ar substantially influences immunity, inducing a sex-biased immune response. This review aims to provide a comprehensive understanding of the current state of teleost ar studies and emphasizes the potential of teleost fishes, given their availability, to find molecular evidence about what gives rise to the spectacular diversity among fish species.
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Affiliation(s)
- Tsukasa Ryu
- Laboratory of Marine Biochemistry, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Keigo Okamoto
- Laboratory of Aquatic Molecular Developmental Biology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Satoshi Ansai
- Laboratory of Genome Editing Breeding, Graduate School of Agriculture, Kyoto University, Kyoto 606-8507, Japan
| | - Miki Nakao
- Laboratory of Marine Biochemistry, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 819-0395, Japan
- Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Anu Kumar
- Commonwealth Scientific and Industrial Research Organization, CSIRO Environment, PMB2, Glen Osmond, 5064 South Australia, Australia
| | - Taisen Iguchi
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Kanagawa 236-0027, Japan
- Noto Marine Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, Ishikawa 927-0553, Japan
| | - Yukiko Ogino
- Laboratory of Aquatic Molecular Developmental Biology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 819-0395, Japan,
- Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
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Jarrett BJM, Miller CW. Host Plant Effects on Sexual Selection Dynamics in Phytophagous Insects. ANNUAL REVIEW OF ENTOMOLOGY 2024; 69:41-57. [PMID: 37562047 DOI: 10.1146/annurev-ento-022823-020258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Natural selection is notoriously dynamic in nature, and so, too, is sexual selection. The interactions between phytophagous insects and their host plants have provided valuable insights into the many ways in which ecological factors can influence sexual selection. In this review, we highlight recent discoveries and provide guidance for future work in this area. Importantly, host plants can affect both the agents of sexual selection (e.g., mate choice and male-male competition) and the traits under selection (e.g., ornaments and weapons). Furthermore, in our rapidly changing world, insects now routinely encounter new potential host plants. The process of adaptation to a new host may be hindered or accelerated by sexual selection, and the unexplored evolutionary trajectories that emerge from these dynamics are relevant to pest management and insect conservation strategies. Examining the effects of host plants on sexual selection has the potential to advance our fundamental understanding of sexual conflict, host range evolution, and speciation, with relevance across taxa.
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Affiliation(s)
- Benjamin J M Jarrett
- School of Natural Sciences, Bangor University, Bangor, United Kingdom;
- Department of Biology, Lund University, Lund, Sweden
- Department of Entomology and Nematology, University of Florida, Gainesville, Florida, USA;
| | - Christine W Miller
- Department of Entomology and Nematology, University of Florida, Gainesville, Florida, USA;
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Hou M, Opedal ØH, Zhao ZG. Sexually concordant selection on floral traits despite greater opportunity for selection through male fitness. THE NEW PHYTOLOGIST 2024; 241:926-936. [PMID: 37899633 DOI: 10.1111/nph.19370] [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: 09/11/2023] [Accepted: 10/16/2023] [Indexed: 10/31/2023]
Abstract
Pollinators are important drivers of floral trait evolution, yet plant populations are not always perfectly adapted to their pollinators. Such apparent maladaptation may result from conflicting selection through male and female sexual functions in hermaphrodites. We studied sex-specific mating patterns and phenotypic selection on floral traits in Aconitum gymnandrum. After genotyping 1786 offspring, we partitioned individual fitness into sex-specific selfed and outcrossed components and estimated phenotypic selection acting through each. Relative fitness increased with increasing mate number, and more so for male function. This led to greater opportunity for selection through outcrossed male fitness, though patterns of phenotypic selection on floral traits tended to be similar, and with better support for selection through female rather than male fitness components. We detected directional selection through one or more fitness component for larger flower number, larger flowers, and more negative nectar gradients within inflorescences. Our results are consistent with Bateman's principles for sex-specific mating patterns and illustrate that, despite the expected difference in opportunity for selection, patterns of variation in selection across traits can be rather similar for the male and female sexual functions. These results shed new light on the effect of sexual selection on the evolution of floral traits.
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Affiliation(s)
- Meng Hou
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
- Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 130102, Changchun, China
| | | | - Zhi-Gang Zhao
- College of Ecology, Lanzhou University, 730000, Lanzhou, China
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10
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Hults CM, Francis RC, Clint EK, Smith W, Sober ER, Garland T, Rhodes JS. Still little evidence sex differences in spatial navigation are evolutionary adaptations. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231532. [PMID: 38234440 PMCID: PMC10791541 DOI: 10.1098/rsos.231532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/20/2023] [Indexed: 01/19/2024]
Abstract
A putative male advantage in wayfinding ability is the most widely documented sex difference in human cognition and has also been observed in other animals. The common interpretation, the sex-specific adaptation hypothesis, posits that this male advantage evolved as an adaptive response to sex differences in home range size. A previous study a decade ago tested this hypothesis by comparing sex differences in home range size and spatial ability among 11 species and found no relationship. However, the study was limited by the small sample size, the lack of species with a larger female home range and the lack of non-Western human data. The present study represents an update that addresses all of these limitations, including data from 10 more species and from human subsistence cultures. Consistent with the previous result, we found little evidence that sex differences in spatial navigation and home range size are related. We conclude that sex differences in spatial ability are more likely due to experiential factors and/or unselected biological side effects, rather than functional outcomes of natural selection.
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Affiliation(s)
- Connor M. Hults
- Department of Psychology, University of Illinois, 603 E. Daniel St., Champaign, IL 61820, USA
| | | | - Edward K. Clint
- Department of Humanities and Social Sciences, Oregon Institute of Technology, Klamath Falls, OR, USA
| | - Winter Smith
- Department of Humanities and Social Sciences, Oregon Institute of Technology, Klamath Falls, OR, USA
| | - Elliott R. Sober
- Department of Philosophy, University of Wisconsin, Madison, WI, USA
| | - Theodore Garland
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA, USA
| | - Justin S. Rhodes
- Department of Psychology, University of Illinois, 603 E. Daniel St., Champaign, IL 61820, USA
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11
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Islam M, Behura SK. Role of paralogs in the sex-bias transcriptional and metabolic regulation of the brain-placental axis in mice. Placenta 2024; 145:143-150. [PMID: 38134547 DOI: 10.1016/j.placenta.2023.12.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023]
Abstract
INTRODUCTION Duplicated genes or paralogs play important roles in the adaptive function of eukaryotic genomes. Animal studies have shown evidence for the functional role of paralogs in pregnancy, but our knowledge about the role of paralogs in the fetoplacental regulation remains limited. In particular, if fetoplacental metabolic regulation is modulated by differential expression of paralogs remains unexamined. METHODS In this study, gene expression profiles of day-15 placenta and fetal brain were compared to identify families or groups of paralogous genes expressed in the placenta and brain of male versus female fetuses in mice. A Bayesian modeling was applied to infer directional relationship of transcriptional variation of the paralogs relative to the phylogenetic variation of the genes in each family. Gas chromatography-mass spectrometry (GC-MS) was used to perform untargeted metabolomics analysis of day-15 placenta and fetal brain of both sexes. RESULTS We identified paralog groups that were expressed in a sex and/or tissue biased manner between the placenta and fetal brain. Bayesian modeling showed evidence for directional relationship between expression and phylogeny of specific paralogs. These relationships were sex specific. GC-MS analysis identified metabolites that were expressed in a sex-bias manner between the placenta and fetal brain. By performing integrative analysis of the metabolomics and gene expression data, we showed that specific groups of metabolites and paralogous genes were expressed in a coordinated manner between the placenta and fetal brain. DISCUSSION The findings of this study collectively suggest that paralogs play an influential role in the regulation of the brain-placental axis in mice.
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Affiliation(s)
- Maliha Islam
- Division of Animal Sciences, University of Missouri, 920 East Campus Drive, Columbia, Missouri, 65211, USA
| | - Susanta K Behura
- Division of Animal Sciences, University of Missouri, 920 East Campus Drive, Columbia, Missouri, 65211, USA; MU Institute for Data Science and Informatics, University of Missouri, USA; Interdisciplinary Reproduction and Health Group, University of Missouri, USA; Interdisciplinary Neuroscience Program, University of Missouri, USA.
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12
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Chen KH, Pannell JR. Unisexual flowers as a resolution to intralocus sexual conflict in hermaphrodites. Proc Biol Sci 2023; 290:20232137. [PMID: 38018108 PMCID: PMC10685137 DOI: 10.1098/rspb.2023.2137] [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: 09/19/2023] [Accepted: 11/01/2023] [Indexed: 11/30/2023] Open
Abstract
In dioecious populations, males and females may evolve different trait values to increase fitness through their respective sexual functions. Because hermaphrodites express both sexual functions, resolving sexual conflict is potentially more difficult for them. Here, we show that hermaphrodite plants can partially resolve sexual conflict by expressing different trait values in different male and female modules (e.g. different flowers, inflorescences, branches etc.). We analysed the flowering phenology, sex allocation and selection gradients on floral traits of flowers of the andromonoecious plant Pulsatilla alpina, which produces both bisexual and male flowers. Our results indicate that strong protogyny prevents early bisexual flowers from profiting from high siring opportunities early in the reproductive season at a time when male flowers could achieve high siring success. The production of unisexual male flowers thus resolves this sexual conflict because it allows the flowers to express their male function without waiting until after the female function has been performed. Our study illustrates the resolution of sexual conflict arising from phenological constraints via modular divergence in sex allocation. We discuss the extent to which modular variation in sex allocation in the context of other sexual systems may be similarly explained.
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Affiliation(s)
- Kai-Hsiu Chen
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | - John R. Pannell
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
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13
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Kralj-Fišer S, Kuntner M, Debes PV. Sex-specific trait architecture in a spider with sexual size dimorphism. J Evol Biol 2023; 36:1428-1437. [PMID: 37702091 DOI: 10.1111/jeb.14217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 06/23/2023] [Accepted: 06/28/2023] [Indexed: 09/14/2023]
Abstract
Sexual dimorphism, or sex-specific trait expression, may evolve when selection favours different optima for the same trait between sexes, that is, under antagonistic selection. Intra-locus sexual conflict exists when the sexually dimorphic trait under antagonistic selection is based on genes shared between sexes. A common assumption is that the presence of sexual-size dimorphism (SSD) indicates that sexual conflict has been, at least partly, resolved via decoupling of the trait architecture between sexes. However, whether and how decoupling of the trait architecture between sexes has been realized often remains unknown. We tested for differences in architecture of adult body size between sexes in a species with extreme SSD, the African hermit spider (Nephilingis cruentata), where adult female body size greatly exceeds that of males. Specifically, we estimated the sex-specific importance of genetic and maternal effects on adult body size among individuals that we laboratory-reared for up to eight generations. Quantitative genetic model estimates indicated that size variation in females is to a larger extent explained by direct genetic effects than by maternal effects, but in males to a larger extent by maternal than by genetic effects. We conclude that this sex-specific body-size architecture enables body-size evolution to proceed much more independently than under a common architecture to both sexes.
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Affiliation(s)
- Simona Kralj-Fišer
- ZRC SAZU, Institute of Biology, Ljubljana, Slovenia
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Koper, Slovenia
| | - Matjaž Kuntner
- ZRC SAZU, Institute of Biology, Ljubljana, Slovenia
- Department of Organisms and Ecosystems Research, National Institute of Biology, Ljubljana, Slovenia
| | - Paul Vincent Debes
- Department of Aquaculture and Fish Biology, Hólar University, Sauðárkrókur, Iceland
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14
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Han CS, Lee B, Moon J. Activity-aggression behavioural syndromes exist in males but not in females of the field cricket Teleogryllus emma. Ecol Evol 2023; 13:e10642. [PMID: 37859828 PMCID: PMC10582681 DOI: 10.1002/ece3.10642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/20/2023] [Accepted: 10/09/2023] [Indexed: 10/21/2023] Open
Abstract
Previous studies on sex differences in behaviour have largely focused on differences in average behaviours between sexes. However, males and females can diverge not only in average behaviours but also in the direction of behavioural correlations at the individual level (i.e. behavioural syndromes). Behavioural syndromes, with their potential to constrain the independent evolution of behaviours, may play a role in shaping sex-specific responses to selection and contributing to the development of sex differences in behaviour. Despite the pivotal role of behavioural syndromes in the evolution of sexual dimorphism in behaviour, robust empirical evidence of sex differences in behavioural syndromes based on repeated measurements of behaviours is scarce. In this study, we conducted repeated measurements of activity and aggression in male and female field crickets Teleogryllus emma, providing evidence of sex differences in the existence of behavioural syndromes. Males exhibited a significantly positive behavioural syndrome between activity and aggression, whereas females, in contrast, did not show any aggressive behaviour, resulting in the absence of such a syndrome. The sex differences in the existence of the activity-aggression behavioural syndromes in this species could be attributed to differences in selection. Selection favouring more active and aggressive males may have shaped a positive activity-aggression behavioural syndrome in males, whereas the absence of selection favouring female aggression may have resulted in the absence of aggression and the related behavioural syndrome in females. However, given the plasticity of behaviour with changes in age or the environment, further research is needed to explore how sex differences in the existence of activity-aggression behavioural syndromes change across contexts. Furthermore, understanding the genetic underpinning of sex differences in a behavioural syndrome would be pivotal to assess the role of behavioural syndromes in the evolution of sexual dimorphism in behaviours.
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Affiliation(s)
- Chang S. Han
- Department of BiologyKyung Hee UniversitySeoulKorea
| | - Byeongho Lee
- Department of BiologyKyung Hee UniversitySeoulKorea
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15
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Singh A, Hasan A, Agrawal AF. An investigation of the sex-specific genetic architecture of fitness in Drosophila melanogaster. Evolution 2023; 77:2015-2028. [PMID: 37329263 DOI: 10.1093/evolut/qpad107] [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: 08/04/2022] [Revised: 05/14/2023] [Accepted: 06/13/2023] [Indexed: 06/19/2023]
Abstract
In dioecious populations, the sexes employ divergent reproductive strategies to maximize fitness and, as a result, genetic variants can affect fitness differently in males and females. Moreover, recent studies have highlighted an important role of the mating environment in shaping the strength and direction of sex-specific selection. Here, we measure adult fitness for each sex of 357 lines from the Drosophila Synthetic Population Resource in two different mating environments. We analyze the data using three different approaches to gain insight into the sex-specific genetic architecture for fitness: classical quantitative genetics, genomic associations, and a mutational burden approach. The quantitative genetics analysis finds that on average segregating genetic variation in this population has concordant fitness effects both across the sexes and across mating environments. We do not find specific genomic regions with strong associations with either sexually antagonistic (SA) or sexually concordant (SC) fitness effects, yet there is modest evidence of an excess of genomic regions with weak associations, with both SA and SC fitness effects. Our examination of mutational burden indicates stronger selection against indels and loss-of-function variants in females than in males.
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Affiliation(s)
- Amardeep Singh
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Asad Hasan
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Aneil F Agrawal
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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16
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Miller SE, Sheehan MJ. Sex differences in deleterious genetic variants in a haplodiploid social insect. Mol Ecol 2023; 32:4546-4556. [PMID: 37350360 PMCID: PMC10528523 DOI: 10.1111/mec.17057] [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: 08/26/2022] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 06/24/2023]
Abstract
Deleterious variants are selected against but can linger in populations at low frequencies for long periods of time, decreasing fitness and contributing to disease burden in humans and other species. Deleterious variants occur at low frequency but distinguishing deleterious variants from low-frequency neutral variation is challenging based on population genomics data alone. As a result, we have little sense of the number and identity of deleterious variants in wild populations. For haplodiploid species, it has been hypothesised that deleterious alleles will be directly exposed to selection in haploid males, but selection can be masked in diploid females when deleterious variants are recessive, resulting in more efficient purging of deleterious mutations in males. Therefore, comparisons of the differences between haploid and diploid genomes from the same population may be a useful method for inferring rare deleterious variants. This study provides the first formal test of this hypothesis. Using wild populations of Northern paper wasps (Polistes fuscatus), we find that males have fewer missense and nonsense variants per generation than females from the same population. Allele frequency differences are especially pronounced for rare missense and nonsense variants and these differences lead to a lower mutational load in males than females. Based on these data we infer that many highly deleterious mutations are segregating in the paper wasp population. Stronger selection against deleterious alleles in haploid males may have implications for adaptation in other haplodiploid insects and provides evidence that wild populations harbour abundant deleterious variants.
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Affiliation(s)
- Sara E. Miller
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
- Department of Biology, University of Missouri St. Louis, St. Louis, MO, USA
| | - Michael J. Sheehan
- Laboratory for Animal Social Evolution and Recognition, Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
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17
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Gamble MM, Calsbeek RG. Sex-specific heritabilities for length at maturity among Pacific salmonids and their consequences for evolution in response to artificial selection. Evol Appl 2023; 16:1458-1471. [PMID: 37622093 PMCID: PMC10445087 DOI: 10.1111/eva.13579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/18/2023] [Accepted: 06/25/2023] [Indexed: 08/26/2023] Open
Abstract
Artificial selection, whether intentional or coincidental, is a common result of conservation policies and natural resource management. To reduce unintended consequences of artificial selection, conservation practitioners must understand both artificial selection gradients on traits of interest and how those traits are correlated with others that may affect population growth and resilience. We investigate how artificial selection on male body size in Pacific salmon (Oncorhynchus spp.) may influence the evolution of female body size and female fitness. While salmon hatchery managers often assume that selection for large males will also produce large females, this may not be the case-in fact, because the fastest-growing males mature earliest and at the smallest size, and because female age at maturity varies little, small males may produce larger females if the genetic architecture of growth rate is the same in both sexes. We explored this possibility by estimating sex-specific heritability values of and natural and artificial selection gradients on length at maturity in four populations representing three species of Pacific salmon. We then used the multivariate breeder's equation to project how artificial selection against small males may affect the evolution of female length and fecundity. Our results indicate that the heritability of length at maturity is greater within than between the sexes and that sire-daughter heritability values are especially small. Salmon hatchery policies should consider these sex-specific quantitative genetic parameters to avoid potential unintended consequences of artificial selection.
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Affiliation(s)
- Madilyn M. Gamble
- Graduate Program in Ecology, Evolution, Ecosystems, and SocietyDartmouth CollegeHanoverNew HampshireUSA
| | - Ryan G. Calsbeek
- Department of Biological SciencesDartmouth CollegeHanoverNew HampshireUSA
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18
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Tosto NM, Beasley ER, Wong BBM, Mank JE, Flanagan SP. The roles of sexual selection and sexual conflict in shaping patterns of genome and transcriptome variation. Nat Ecol Evol 2023; 7:981-993. [PMID: 36959239 DOI: 10.1038/s41559-023-02019-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 02/21/2023] [Indexed: 03/25/2023]
Abstract
Sexual dimorphism is one of the most prevalent, and often the most extreme, examples of phenotypic variation within species, and arises primarily from genomic variation that is shared between females and males. Many sexual dimorphisms arise through sex differences in gene expression, and sex-biased expression is one way that a single, shared genome can generate multiple, distinct phenotypes. Although many sexual dimorphisms are expected to result from sexual selection, and many studies have invoked the possible role of sexual selection to explain sex-specific traits, the role of sexual selection in the evolution of sexually dimorphic gene expression remains difficult to differentiate from other forms of sex-specific selection. In this Review, we propose a holistic framework for the study of sex-specific selection and transcriptome evolution. We advocate for a comparative approach, across tissues, developmental stages and species, which incorporates an understanding of the molecular mechanisms, including genomic variation and structure, governing gene expression. Such an approach is expected to yield substantial insights into the evolution of genetic variation and have important applications in a variety of fields, including ecology, evolution and behaviour.
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Affiliation(s)
- Nicole M Tosto
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Emily R Beasley
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Bob B M Wong
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Judith E Mank
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sarah P Flanagan
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
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19
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Chen P, Aravin AA. Genetic control of a sex-specific piRNA program. Curr Biol 2023; 33:1825-1835.e3. [PMID: 37059098 PMCID: PMC10431932 DOI: 10.1016/j.cub.2023.03.057] [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: 11/17/2022] [Revised: 02/15/2023] [Accepted: 03/17/2023] [Indexed: 04/16/2023]
Abstract
Sexually dimorphic traits in morphologies are widely studied,1,2,3,4 but those in essential molecular pathways remain largely unexplored. Previous work showed substantial sex differences in Drosophila gonadal piRNAs,5 which guide PIWI proteins to silence selfish genetic elements, thereby safeguarding fertility.6,7,8 However, the genetic control mechanisms of piRNA sexual dimorphism remain unknown. Here, we showed that most sex differences in the piRNA program originate from the germ line rather than the gonadal somatic cells. Building on this, we dissected the contribution of sex chromosomes and cellular sexual identity toward the sex-specific germline piRNA program. We found that the presence of the Y chromosome is sufficient to recapitulate some aspects of the male piRNA program in a female cellular environment. Meanwhile, sexual identity controls the sexually divergent piRNA production from X-linked and autosomal loci, revealing a crucial input from sex determination into piRNA biogenesis. Sexual identity regulates piRNA biogenesis through Sxl, and this effect is mediated, in part, through chromatin proteins Phf7 and Kipferl. Together, our work delineated the genetic control of a sex-specific piRNA program, where sex chromosomes and sexual identity collectively sculpt an essential molecular trait.
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Affiliation(s)
- Peiwei Chen
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
| | - Alexei A Aravin
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
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20
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Nanni AV, Martinez N, Graze R, Morse A, Newman JRB, Jain V, Vlaho S, Signor S, Nuzhdin SV, Renne R, McIntyre LM. Sex-Biased Expression Is Associated With Chromatin State in Drosophila melanogaster and Drosophila simulans. Mol Biol Evol 2023; 40:msad078. [PMID: 37116218 PMCID: PMC10162771 DOI: 10.1093/molbev/msad078] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 02/24/2023] [Accepted: 03/13/2023] [Indexed: 04/30/2023] Open
Abstract
In Drosophila melanogaster and D. simulans head tissue, 60% of orthologous genes show evidence of sex-biased expression in at least one species. Of these, ∼39% (2,192) are conserved in direction. We hypothesize enrichment of open chromatin in the sex where we see expression bias and closed chromatin in the opposite sex. Male-biased orthologs are significantly enriched for H3K4me3 marks in males of both species (∼89% of male-biased orthologs vs. ∼76% of unbiased orthologs). Similarly, female-biased orthologs are significantly enriched for H3K4me3 marks in females of both species (∼90% of female-biased orthologs vs. ∼73% of unbiased orthologs). The sex-bias ratio in female-biased orthologs was similar in magnitude between the two species, regardless of the closed chromatin (H3K27me2me3) marks in males. However, in male-biased orthologs, the presence of H3K27me2me3 in both species significantly reduced the correlation between D. melanogaster sex-bias ratio and the D. simulans sex-bias ratio. Male-biased orthologs are enriched for evidence of positive selection in the D. melanogaster group. There are more male-biased genes than female-biased genes in both species. For orthologs with gains/losses of sex-bias between the two species, there is an excess of male-bias compared to female-bias, but there is no consistent pattern in the relationship between H3K4me3 or H3K27me2me3 chromatin marks and expression. These data suggest chromatin state is a component of the maintenance of sex-biased expression and divergence of sex-bias between species is reflected in the complexity of the chromatin status.
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Affiliation(s)
- Adalena V Nanni
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL
| | - Natalie Martinez
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Rita Graze
- Department of Biological Sciences, Auburn University, Auburn, AL
| | - Alison Morse
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL
| | - Jeremy R B Newman
- University of Florida Genetics Institute, University of Florida, Gainesville, FL
| | - Vaibhav Jain
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Srna Vlaho
- Department of Biological Sciences, University of Southern California, Los Angeles, CA
| | - Sarah Signor
- Department of Biological Sciences, North Dakota State University, Fargo, ND
| | - Sergey V Nuzhdin
- Department of Biological Sciences, University of Southern California, Los Angeles, CA
| | - Rolf Renne
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL
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21
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Kaufmann P, Howie JM, Immonen E. Sexually antagonistic selection maintains genetic variance when sexual dimorphism evolves. Proc Biol Sci 2023; 290:20222484. [PMID: 36946115 PMCID: PMC10031426 DOI: 10.1098/rspb.2022.2484] [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: 12/12/2022] [Accepted: 02/28/2023] [Indexed: 03/23/2023] Open
Abstract
Genetic variance (VG) in fitness related traits is often unexpectedly high, evoking the question how VG can be maintained in the face of selection. Sexually antagonistic (SA) selection favouring alternative alleles in the sexes is common and predicted to maintain VG, while directional selection should erode it. Both SA and sex-limited directional selection can lead to sex-specific adaptations but how each affect VG when sexual dimorphism evolves remain experimentally untested. Using replicated artificial selection on the seed beetle Callosobruchus maculatus body size we recently demonstrated an increase in size dimorphism under SA and male-limited (ML) selection by 50% and 32%, respectively. Here we test their consequences on genetic variation. We show that SA selection maintained significantly more ancestral, autosomal additive genetic variance than ML selection, while both eroded sex-linked additive variation equally. Ancestral female-specific dominance variance was completely lost under ML, while SA selection consistently sustained it. Further, both forms of selection preserved a high genetic correlation between the sexes (rm,f). These results demonstrate the potential for sexual antagonism to maintain more genetic variance while fuelling sex-specific adaptation in a short evolutionary time scale, and are in line with predicted importance of sex-specific dominance reducing sexual conflict over alternative alleles.
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Affiliation(s)
- Philipp Kaufmann
- Department of Ecology and Genetics (Evolutionary Biology program), Uppsala University, Norbyvägen 18D, 75234 Uppsala, Sweden
| | - James Malcolm Howie
- Department of Ecology and Genetics (Evolutionary Biology program), Uppsala University, Norbyvägen 18D, 75234 Uppsala, Sweden
- Institute of Forest Entomology, Forest Pathology and Forest Protection, Boku, University of Natural Resources and Life Sciences, Peter-Jordan-Straße 82/I, 1190, Vienna, Austria
| | - Elina Immonen
- Department of Ecology and Genetics (Evolutionary Biology program), Uppsala University, Norbyvägen 18D, 75234 Uppsala, Sweden
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22
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Evolutionary differentiation of androgen receptor is responsible for sexual characteristic development in a teleost fish. Nat Commun 2023; 14:1428. [PMID: 36918573 PMCID: PMC10014959 DOI: 10.1038/s41467-023-37026-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 02/28/2023] [Indexed: 03/16/2023] Open
Abstract
Teleost fishes exhibit complex sexual characteristics in response to androgens, such as fin enlargement and courtship display. However, the molecular mechanisms underlying their evolutionary acquisition remain largely unknown. To address this question, we analyse medaka (Oryzias latipes) mutants deficient in teleost-specific androgen receptor ohnologs (ara and arb). We discovered that neither ar ohnolog was required for spermatogenesis, whilst they appear to be functionally redundant for the courtship display in males. However, both were required for reproductive success: ara for tooth enlargement and the reproductive behaviour eliciting female receptivity, arb for male-specific fin morphogenesis and sexual motivation. We further showed that differences between the two ar ohnologs in their transcription, cellular localisation of their encoded proteins, and their downstream genetic programmes could be responsible for the phenotypic diversity between the ara and arb mutants. These findings suggest that the ar ohnologs have diverged in two ways: first, through the loss of their roles in spermatogenesis and second, through gene duplication followed by functional differentiation that has likely resolved the pleiotropic roles derived from their ancestral gene. Thus, our results provide insights into how genome duplication impacts the massive diversification of sexual characteristics in the teleost lineage.
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23
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Layh S, Nagarajan-Radha V, Lemos B, Dowling DK. Y chromosome-linked variation affects locomotor activity in male Drosophila melanogaster and is robust to differences in thermal environment. Heredity (Edinb) 2023; 130:312-319. [PMID: 36914794 PMCID: PMC10163223 DOI: 10.1038/s41437-023-00604-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 03/16/2023] Open
Abstract
Although containing genes important for sex determination, genetic variation within the Y chromosome was traditionally predicted to contribute little to the expression of sexually dimorphic traits. This prediction was shaped by the assumption that the chromosome harbours few protein-coding genes, and that capacity for Y-linked variation to shape adaptation would be hindered by the chromosome's lack of recombination and holandric inheritance. Consequently, most studies exploring the genotypic contributions to sexually dimorphic traits have focused on the autosomes and X chromosome. Yet, several studies have now demonstrated that the Y chromosome harbours variation affecting male fitness, moderating the expression of hundreds of genes across the nuclear genome. Furthermore, emerging results have shown that expression of this Y-linked variation may be sensitive to environmental heterogeneity, leading to the prediction that Y-mediated gene-by-environment interactions will shape the expression of sexually dimorphic phenotypes. We tested this prediction, investigating whether genetic variation across six distinct Y chromosome haplotypes affects the expression of locomotor activity, at each of two temperatures (20 and 28 °C) in male fruit flies (Drosophila melanogaster). Locomotor activity is a sexually dimorphic trait in this species, previously demonstrated to be under intralocus sexual conflict. We demonstrate Y haplotype effects on male locomotor activity, but the rank order and magnitude of these effects were unaltered by differences in temperature. Our study contributes to a growing number of studies demonstrating Y-linked effects moderating expression of traits evolving under sexually antagonistic selection, suggesting a role for the Y chromosome in shaping outcomes of sexual conflict.
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Affiliation(s)
- Sean Layh
- School of Biological Sciences, Monash University, Melbourne, VIC, Australia
| | - Venkatesh Nagarajan-Radha
- School of Biological Sciences, Monash University, Melbourne, VIC, Australia.,Behaviour Ecology and Evolution Lab, School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW, Australia
| | - Bernardo Lemos
- Molecular and Integrative Physiological Sciences Program, Department of Environmental Health, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Damian K Dowling
- School of Biological Sciences, Monash University, Melbourne, VIC, Australia.
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24
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Nanni AV, Martinez N, Graze R, Morse A, Newman JRB, Jain V, Vlaho S, Signor S, Nuzhdin SV, Renne R, McIntyre LM. Sex-biased expression is associated with chromatin state in D. melanogaster and D. simulans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523946. [PMID: 36711631 PMCID: PMC9882225 DOI: 10.1101/2023.01.13.523946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We propose a new model for the association of chromatin state and sex-bias in expression. We hypothesize enrichment of open chromatin in the sex where we see expression bias (OS) and closed chromatin in the opposite sex (CO). In this study of D. melanogaster and D. simulans head tissue, sex-bias in expression is associated with H3K4me3 (open mark) in males for male-biased genes and in females for female-biased genes in both species. Sex-bias in expression is also largely conserved in direction and magnitude between the two species on the X and autosomes. In male-biased orthologs, the sex-bias ratio is more divergent between species if both species have H3K27me2me3 marks in females compared to when either or neither species has H3K27me2me3 in females. H3K27me2me3 marks in females are associated with male-bias in expression on the autosomes in both species, but on the X only in D. melanogaster . In female-biased orthologs the relationship between the species for the sex-bias ratio is similar regardless of the H3K27me2me3 marks in males. Female-biased orthologs are more similar in the ratio of sex-bias than male-biased orthologs and there is an excess of male-bias in expression in orthologs that gain/lose sex-bias. There is an excess of male-bias in sex-limited expression in both species suggesting excess male-bias is due to rapid evolution between the species. The X chromosome has an enrichment in male-limited H3K4me3 in both species and an enrichment of sex-bias in expression compared to the autosomes.
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Affiliation(s)
- Adalena V Nanni
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Natalie Martinez
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Rita Graze
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Alison Morse
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Jeremy R B Newman
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Vaibhav Jain
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Srna Vlaho
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Sarah Signor
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Sergey V Nuzhdin
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Rolf Renne
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
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25
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Gao JJ, Barmina O, Thompson A, Kim BY, Suvorov A, Tanaka K, Watabe H, Toda MJ, Chen JM, Katoh TK, Kopp A. Secondary reversion to sexual monomorphism associated with tissue-specific loss of doublesex expression. Evolution 2022; 76:2089-2104. [PMID: 35841603 DOI: 10.1111/evo.14564] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 01/22/2023]
Abstract
Animal evolution is characterized by frequent turnover of sexually dimorphic traits-new sex-specific characters are gained, and some ancestral sex-specific characters are lost, in many lineages. In insects, sexual differentiation is predominantly cell autonomous and depends on the expression of the doublesex (dsx) transcription factor. In most cases, cells that transcribe dsx have the potential to undergo sex-specific differentiation, while those that lack dsx expression do not. Consistent with this mode of development, comparative research has shown that the origin of new sex-specific traits can be associated with the origin of new spatial domains of dsx expression. In this report, we examine the opposite situation-a secondary loss of the sex comb, a male-specific grasping structure that develops on the front legs of some drosophilid species. We show that while the origin of the sex comb is linked to an evolutionary gain of dsx expression in the leg, sex comb loss in a newly identified species of Lordiphosa (Drosophilidae) is associated with a secondary loss of dsx expression. We discuss how the developmental control of sexual dimorphism affects the mechanisms by which sex-specific traits can evolve.
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Affiliation(s)
- Jian-Jun Gao
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, China.,State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan University, China
| | - Olga Barmina
- Department of Evolution and Ecology, University of California Davis, Davis, CA, 95616, USA
| | - Ammon Thompson
- Department of Evolution and Ecology, University of California Davis, Davis, CA, 95616, USA
| | - Bernard Y Kim
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Anton Suvorov
- Department of Genetics, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Kohtaro Tanaka
- Department of Evolution and Ecology, University of California Davis, Davis, CA, 95616, USA
| | - Hideaki Watabe
- The Hokkaido University Museum, Kita-10, Nishi-8, Kitaku, Sapporo, 060-0810, Japan
| | - Masanori J Toda
- The Hokkaido University Museum, Kita-10, Nishi-8, Kitaku, Sapporo, 060-0810, Japan
| | - Ji-Min Chen
- State Key Laboratory for Conservation and Utilization of Bioresources in Yunnan, Yunnan University, China
| | - Takehiro K Katoh
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, China
| | - Artyom Kopp
- Department of Evolution and Ecology, University of California Davis, Davis, CA, 95616, USA
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Polygenic signals of sex differences in selection in humans from the UK Biobank. PLoS Biol 2022; 20:e3001768. [PMID: 36067235 PMCID: PMC9481184 DOI: 10.1371/journal.pbio.3001768] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 09/16/2022] [Accepted: 07/27/2022] [Indexed: 11/19/2022] Open
Abstract
Sex differences in the fitness effects of genetic variants can influence the rate of adaptation and the maintenance of genetic variation. For example, "sexually antagonistic" (SA) variants, which are beneficial for one sex and harmful for the other, can both constrain adaptation and increase genetic variability for fitness components such as survival, fertility, and disease susceptibility. However, detecting variants with sex-differential fitness effects is difficult, requiring genome sequences and fitness measurements from large numbers of individuals. Here, we develop new theory for studying sex-differential selection across a complete life cycle and test our models with genotypic and reproductive success data from approximately 250,000 UK Biobank individuals. We uncover polygenic signals of sex-differential selection affecting survival, reproductive success, and overall fitness, with signals of sex-differential reproductive selection reflecting a combination of SA polymorphisms and sexually concordant polymorphisms in which the strength of selection differs between the sexes. Moreover, these signals hold up to rigorous controls that minimise the contributions of potential confounders, including sequence mapping errors, population structure, and ascertainment bias. Functional analyses reveal that sex-differentiated sites are enriched in phenotype-altering genomic regions, including coding regions and loci affecting a range of quantitative traits. Population genetic analyses show that sex-differentiated sites exhibit evolutionary histories dominated by genetic drift and/or transient balancing selection, but not long-term balancing selection, which is consistent with theoretical predictions of effectively weak SA balancing selection in historically small populations. Overall, our results are consistent with polygenic sex-differential-including SA-selection in humans. Evidence for sex-differential selection is particularly strong for variants affecting reproductive success, in which the potential contributions of nonrandom sampling to signals of sex differentiation can be excluded.
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Multivariate selection and the making and breaking of mutational pleiotropy. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10195-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractThe role of mutations have been subject to many controversies since the formation of the Modern Synthesis of evolution in the early 1940ties. Geneticists in the early half of the twentieth century tended to view mutations as a limiting factor in evolutionary change. In contrast, natural selection was largely viewed as a “sieve” whose main role was to sort out the unfit but which could not create anything novel alone. This view gradually changed with the development of mathematical population genetics theory, increased appreciation of standing genetic variation and the discovery of more complex forms of selection, including balancing selection. Short-term evolutionary responses to selection are mainly influenced by standing genetic variation, and are predictable to some degree using information about the genetic variance–covariance matrix (G) and the strength and form of selection (e. g. the vector of selection gradients, β). However, predicting long-term evolution is more challenging, and requires information about the nature and supply of novel mutations, summarized by the mutational variance–covariance matrix (M). Recently, there has been increased attention to the role of mutations in general and M in particular. Some evolutionary biologists argue that evolution is largely mutation-driven and claim that mutation bias frequently results in mutation-biased adaptation. Strong similarities between G and M have also raised questions about the non-randomness of mutations. Moreover, novel mutations are typically not isotropic in their phenotypic effects and mutational pleiotropy is common. Here I discuss the evolutionary origin and consequences of mutational pleiotropy and how multivariate selection directly shapes G and indirectly M through changed epistatic relationships. I illustrate these ideas by reviewing recent literature and models about correlational selection, evolution of G and M, sexual selection and the fitness consequences of sexual antagonism.
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Hoops D, Whiting MJ, Keogh JS. A Smaller Habenula is Associated with Increasing Intensity of Sexual Selection. BRAIN, BEHAVIOR AND EVOLUTION 2022; 97:265-273. [PMID: 34983044 DOI: 10.1159/000521750] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 12/18/2021] [Indexed: 11/19/2022]
Abstract
The habenula is a small structure in the brain that acts as a relay station for neural information, helping to modulate behaviour in response to variable and unpredictable stimuli. Broadly, it is evolutionarily conserved in structure and connectivity across vertebrates and is the most prominent bilaterally asymmetric structure in the brain. Nonetheless, comparative evolutionary studies of the habenula are virtually non-existent. Here, we examine the volumes of the medial and lateral habenular subregions, in both hemispheres, across a group of Australian agamid lizards in the genus Ctenophorus. In males, we found bilaterally asymmetrical selection on the lateral habenula to become smaller with increasing intensity of sexual selection, possibly as a mechanism to increase aggressive responses. In females, we found bilaterally symmetrical selection on both the medial and lateral subregions to become smaller with increasing sexual selection. This is consistent with sexual selection increasing motivation to reproduce and the habenula's well-characterized role in controlling and modifying responses to rewarding stimuli. However, as there are currently no studies addressing habenular function in reptiles, it is difficult to draw more precise conclusions. As has happened recently in biomedical neuroscience, it is time for the habenula to receive greater attention in evolutionary neuroscience.
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Affiliation(s)
- Daniel Hoops
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia.,Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Martin J Whiting
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - J Scott Keogh
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Acton, Australian Capital Territory, Australia
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Parrett JM, Chmielewski S, Aydogdu E, Łukasiewicz A, Rombauts S, Szubert-Kruszyńska A, Babik W, Konczal M, Radwan J. Genomic evidence that a sexually selected trait captures genome-wide variation and facilitates the purging of genetic load. Nat Ecol Evol 2022; 6:1330-1342. [DOI: 10.1038/s41559-022-01816-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/26/2022] [Indexed: 10/17/2022]
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30
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An Overview of Interlocation Sexual Shape Dimorphism in Caquetaia kraussi (Perciformes: Cichlidae) A Geometric Morphometric Approach. FISHES 2022. [DOI: 10.3390/fishes7040146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
C. kraussii is an endemic fish species from Colombia and Venezuela and represents a valuable food resource for local human communities. Due to its economic importance, the management and captive breeding of this species are of special interest. However, the anatomical similarities between sexes have been a problem for visual identification. It is also important to indicate that C. kraussii has cryptic morphological behavior between sexes, a topic that has been one of the main problems for the implementation of management plans. The following research studied individuals from three different localities along the Canal del Dique, Bolívar Department in Colombia, in which the body shape of C. kraussii was analyzed using geometric morphometric analysis. The analyses detected the presence of intralocality sexual dimorphism in two of the three localities analyzed, showing a low morphological variability among males, presenting conserved body shape, as well as a greater morphological disparity among females. This sexual shape dimorphism may be associated with the environmental variation among different locations. These results suggest the presence of two evolutionary forces acting asymmetrically between the sexes of C. kraussii, with males mostly subject to sexual selection pressure, while females are mainly subject to environmental pressures.
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31
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How does selection shape spatial memory in the wild? Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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32
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Olito C, Vries CD. The demographic costs of sexually antagonistic selection in partially selfing populations. Am Nat 2022; 200:401-418. [DOI: 10.1086/720419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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33
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Modelling Climate Change Impacts on Tropical Dry Forest Fauna. SUSTAINABILITY 2022. [DOI: 10.3390/su14084760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Tropical dry forests are among the most threatened ecosystems in the world, and those occurring in the insular Caribbean are particularly vulnerable. Climate change represents a significant threat for the Caribbean region and for small islands like Jamaica. Using the Hellshire Hills protected area in Jamaica, a simple model was developed to project future abundance of arthropods and lizards based on current sensitivities to climate variables derived from rainfall and temperature records. The abundances of 20 modelled taxa were predicted more often by rainfall variables than temperature, but both were found to have strong impacts on arthropod and lizard abundance. Most taxa were projected to decrease in abundance by the end of the century under drier and warmer conditions. Where an increase in abundance was projected under a low emissions scenario, this change was reduced or reversed under a high emissions climate change scenario. The validation process showed that, even for a small population, there was reasonable skill in predicting its annual variability. Results of this study show that this simple model can be used to identify the vulnerability of similar sites to the effects of shifting climate and, by extension, their conservation needs.
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34
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Penn DJ, Zala SM, Luzynski KC. Regulation of Sexually Dimorphic Expression of Major Urinary Proteins. Front Physiol 2022; 13:822073. [PMID: 35431992 PMCID: PMC9008510 DOI: 10.3389/fphys.2022.822073] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/21/2022] [Indexed: 11/15/2022] Open
Abstract
Male house mice excrete large amounts of protein in their urinary scent marks, mainly composed of Major Urinary Proteins (MUPs), and these lipocalins function as pheromones and pheromone carriers. Here, we review studies on sexually dimorphic MUP expression in house mice, including the proximate mechanisms controlling MUP gene expression and their adaptive functions. Males excrete 2 to 8 times more urinary protein than females, though there is enormous variation in gene expression across loci in both sexes. MUP expression is dynamically regulated depending upon a variety of factors. Males regulate MUP expression according to social status, whereas females do not, and males regulate expression depending upon health and condition. Male-biased MUP expression is regulated by pituitary secretion of growth hormone (GH), which binds receptors in the liver, activating the JAK2-STAT5 signaling pathway, chromatin accessibility, and MUP gene transcription. Pulsatile male GH secretion is feminized by several factors, including caloric restriction, microbiota depletion, and aging, which helps explain condition-dependent MUP expression. If MUP production has sex-specific fitness optima, then this should generate sexual antagonism over allelic expression (intra-locus sexual conflict) selectively favoring sexually dimorphic expression. MUPs influence the sexual attractiveness of male urinary odor and increased urinary protein excretion is correlated with the reproductive success of males but not females. This finding could explain the selective maintenance of sexually dimorphic MUP expression. Producing MUPs entails energetic costs, but increased excretion may reduce the net energetic costs and predation risks from male scent marking as well as prolong the release of chemical signals. MUPs may also provide physiological benefits, including regulating metabolic rate and toxin removal, which may have sex-specific effects on survival. A phylogenetic analysis on the origins of male-biased MUP gene expression in Mus musculus suggests that this sexual dimorphism evolved by increasing male MUP expression rather than reducing female expression.
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35
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Boisseau RP, Büscher TH, Klawitter LJ, Gorb SN, Emlen DJ, Tobalske BW. Multi-modal locomotor costs favor smaller males in a sexually dimorphic leaf-mimicking insect. BMC Ecol Evol 2022; 22:39. [PMID: 35350992 PMCID: PMC8962604 DOI: 10.1186/s12862-022-01993-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/16/2022] [Indexed: 11/28/2022] Open
Abstract
Background In most arthropods, adult females are larger than males, and male competition is a race to quickly locate and mate with scattered females (scramble competition polygyny). Variation in body size among males may confer advantages that depend on context. Smaller males may be favored due to more efficient locomotion leading to higher mobility during mate searching. Alternatively, larger males may benefit from increased speed and higher survivorship. While the relationship between male body size and mobility has been investigated in several systems, how different aspects of male body morphology specifically affect their locomotor performance in different contexts is often unclear. Results Using a combination of empirical measures of flight performance and modelling of body aerodynamics, we show that large body size impairs flight performance in male leaf insects (Phyllium philippinicum), a species where relatively small and skinny males fly through the canopy in search of large sedentary females. Smaller males were more agile in the air and ascended more rapidly during flight. Our models further predicted that variation in body shape would affect body lift and drag but suggested that flight costs may not explain the evolution of strong sexual dimorphism in body shape in this species. Finally, empirical measurements of substrate adhesion and subsequent modelling of landing impact forces suggested that smaller males had a lower risk of detaching from the substrates on which they walk and land. Conclusions By showing that male body size impairs their flight and substrate adhesion performance, we provide support to the hypothesis that smaller scrambling males benefit from an increased locomotor performance and shed light on the evolution of sexual dimorphism in scramble competition mating systems. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-01993-z.
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Affiliation(s)
- Romain P Boisseau
- Division of Biological Sciences, University of Montana, 32 Campus Dr, Missoula, MT, 59812, USA.
| | - Thies H Büscher
- Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24098, Kiel, Germany
| | - Lexi J Klawitter
- Division of Biological Sciences, University of Montana, 32 Campus Dr, Missoula, MT, 59812, USA
| | - Stanislav N Gorb
- Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24098, Kiel, Germany
| | - Douglas J Emlen
- Division of Biological Sciences, University of Montana, 32 Campus Dr, Missoula, MT, 59812, USA
| | - Bret W Tobalske
- Division of Biological Sciences, University of Montana, 32 Campus Dr, Missoula, MT, 59812, USA
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36
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Ruzicka F, Connallon T. An unbiased test reveals no enrichment of sexually antagonistic polymorphisms on the human X chromosome. Proc Biol Sci 2022; 289:20212314. [PMID: 35078366 PMCID: PMC8790371 DOI: 10.1098/rspb.2021.2314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Mutations with beneficial effects in one sex can have deleterious effects in the other. Such 'sexually antagonistic' (SA) variants contribute to variation in life-history traits and overall fitness, yet their genomic distribution is poorly resolved. Theory predicts that SA variants could be enriched on the X chromosome or autosomes, yet current empirical tests face two formidable challenges: (i) identifying SA selection in genomic data is difficult; and (ii) metrics of SA variation show persistent biases towards the X, even when SA variants are randomly distributed across the genome. Here, we present an unbiased test of the theory that SA variants are enriched on the X. We first develop models for reproductive FST-a metric for quantifying sex-differential (including SA) effects of genetic variants on lifetime reproductive success-that control for X-linked biases. Comparing data from approximately 250 000 UK Biobank individuals to our models, we find FST elevations consistent with both X-linked and autosomal SA polymorphisms affecting reproductive success in humans. However, the extent of FST elevations does not differ from a model in which SA polymorphisms are randomly distributed across the genome. We argue that the polygenic nature of SA variation, along with sex asymmetries in SA effects, might render X-linked enrichment of SA polymorphisms unlikely.
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Affiliation(s)
- Filip Ruzicka
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Tim Connallon
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
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37
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Gamble MM, Calsbeek RG. A potential role for restricted intertactical heritability in preventing intralocus conflict. Evol Appl 2021; 14:2576-2590. [PMID: 34815740 PMCID: PMC8591329 DOI: 10.1111/eva.13292] [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: 12/15/2020] [Revised: 08/07/2021] [Accepted: 08/12/2021] [Indexed: 11/29/2022] Open
Abstract
Intralocus sexual conflict, which arises when the same trait has different fitness optima in males and females, reduces population growth rates. Recently, evolutionary biologists have recognized that intralocus conflict can occur between morphs or reproductive tactics within a sex and that intralocus tactical conflict might constrain tactical dimorphism and population growth rates just as intralocus sexual conflict constrains sexual dimorphism and population growth rates. However, research has only recently focused on sexual and tactical intralocus conflict simultaneously, and there is no formal theory connecting the two. We present a graphical model of how tactical and sexual conflict over the same trait could constrain both sexual and tactical dimorphisms. We then use Coho salmon (Oncorhynchus kisutch), an important species currently protected under the Endangered Species Act, to investigate the possibility of simultaneous sexual and tactical conflict. Larger Coho males gain access to females through fighting while smaller males are favored through sneaking tactics, and female reproductive success is positively correlated with length. We tested for antagonistic selection on length at maturity among sexes and tactics and then used parent-offspring regression to calculate sex- and tactic-specific heritabilities to determine whether and where intralocus conflict exists. Selection on length varied in intensity and form among tactics and years. Length was heritable between dams and daughters (h 2 ± 95% CI = 0.361 ± 0.252) and between fighter males and their fighter sons (0.867 ± 0.312), but no other heritabilities differed significantly from zero. The lack of intertactical heritabilities in this system, combined with similar selection on length among tactics, suggests the absence of intralocus conflict between sexes and among tactics, allowing for the evolution of sexual and tactical dimorphisms. Our results suggest that Coho salmon populations are unlikely to be constrained by intralocus conflict or artificial selection on male tactic.
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Affiliation(s)
- Madilyn M. Gamble
- Graduate Program in Ecology, Evolution, Ecosystems, and SocietyDartmouth CollegeHanoverNHUSA
| | - Ryan G. Calsbeek
- Graduate Program in Ecology, Evolution, Ecosystems, and SocietyDartmouth CollegeHanoverNHUSA
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38
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Abstract
A well-known property of sexual selection combined with a cross-sex genetic correlation (rmf) is that it can facilitate a peak shift on the adaptive landscape. How do these diversifying effects of sexual selection + rmf balance with the constraints imposed by such sexual antagonism, to affect the macroevolution of sexual dimorphism? Here, I extend existing quantitative genetic models of evolution on complex adaptive landscapes. Beyond recovering classical predictions for the conditions promoting a peak shift, I show that when rmf is moderate to strong, relatively weak sexual selection is required to induce a peak shift in males only. Increasing the strength of sexual selection leads to a sexually concordant peak shift, suggesting that macroevolutionary rates of sexual dimorphism may be largely decoupled from the strength of within-population sexual selection. Accounting explicitly for demography further reveals that sex-specific peak shifts may be more likely to be successful than concordant shifts in the face of extinction, especially when natural selection is strong. An overarching conclusion is that macroevolutionary patterns of sexual dimorphism are unlikely to be readily explained by within-population estimates of selection or constraint alone.
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Affiliation(s)
- Stephen P De Lisle
- Evolutionary Ecology Unit, Department of Biology, Lund University, Sölvegatan 37 223 62, Lund, Sweden
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39
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De Lisle SP, Bolnick DI. Male and female reproductive fitness costs of an immune response in natural populations . Evolution 2021; 75:2509-2523. [PMID: 33991339 PMCID: PMC8488946 DOI: 10.1111/evo.14266] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 04/20/2021] [Accepted: 04/23/2021] [Indexed: 12/29/2022]
Abstract
Parasites can mediate host fitness both directly, via effects on survival and reproduction, or indirectly by inducing host immune defense with costly side-effects. The evolution of immune defense is determined by a complex interplay of costs and benefits of parasite infection and immune response, all of which may differ for male and female hosts in sexual lineages. Here, we examine fitness costs associated with an inducible immune defense in a fish-cestode host-parasite system. Cestode infection induces peritoneal fibrosis in threespine stickleback (Gasterosteus aculeatus), constraining cestode growth and sometimes encasing and killing the parasite. Surveying two wild populations of stickleback, we confirm that the presence of fibrosis scar tissue is associated with reduced parasite burden in both male and female fish. However, fibrotic fish had lower foraging success and reproductive fitness (reduced female egg production and male nesting success), indicating strong costs of the lingering immunopathology. Consistent with substantial sexually concordant fitness effects of immune response, we find alignment of multivariate selection across the sexes despite sexual antagonism over morphological shape. Although both sexes experienced costs of fibrosis, the net impacts are unequal because in the two study populations females had higher cestode exposure. To evaluate whether this difference in risk should drive sex-specific immune strategies, we analyze a quantitative genetic model of host immune response to a trophically transmitted parasite. The model and empirical data illustrate how shared costs and benefits of immune response lead to shared evolutionary interests of male and female hosts, despite unequal infection risks across the sexes.
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Affiliation(s)
- Stephen P. De Lisle
- Department of Ecology & Evolutionary Biology University of Connecticut Storrs, CT 06269
- Department of Biology, Evolutionary Ecology Unit, Lund University, Lund, Sweden
| | - Daniel I. Bolnick
- Department of Ecology & Evolutionary Biology University of Connecticut Storrs, CT 06269
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40
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Kaufmann P, Wolak ME, Husby A, Immonen E. Rapid evolution of sexual size dimorphism facilitated by Y-linked genetic variance. Nat Ecol Evol 2021; 5:1394-1402. [PMID: 34413504 DOI: 10.1038/s41559-021-01530-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 07/09/2021] [Indexed: 02/06/2023]
Abstract
Sexual dimorphism is ubiquitous in nature but its evolution is puzzling given that the mostly shared genome constrains independent evolution in the sexes. Sex differences should result from asymmetries between the sexes in selection or genetic variation but studies investigating both simultaneously are lacking. Here, we combine a quantitative genetic analysis of body size variation, partitioned into autosomal and sex chromosome contributions and ten generations of experimental evolution to dissect the evolution of sexual body size dimorphism in seed beetles (Callosobruchus maculatus) subjected to sexually antagonistic or sex-limited selection. Female additive genetic variance (VA) was primarily linked to autosomes, exhibiting a strong intersexual genetic correlation with males ([Formula: see text] = 0.926), while X- and Y-linked genes further contributed to the male VA and X-linked genes contributed to female dominance variance. Consistent with these estimates, sexual body size dimorphism did not evolve in response to female-limited selection but evolved by 30-50% under male-limited and sexually antagonistic selection. Remarkably, Y-linked variance alone could change dimorphism by 30%, despite the C. maculatus Y chromosome being small and heterochromatic. Our results demonstrate how the potential for sexual dimorphism to evolve depends on both its underlying genetic basis and the nature of sex-specific selection.
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Affiliation(s)
- Philipp Kaufmann
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
| | - Matthew E Wolak
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Arild Husby
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Elina Immonen
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
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41
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Sowersby W, Eckerström-Liedholm S, Rowiński PK, Balogh J, Eiler S, Upstone JD, Gonzalez-Voyer A, Rogell B. The relative effects of pace of life-history and habitat characteristics on the evolution of sexual ornaments: A comparative assessment. Evolution 2021; 76:114-127. [PMID: 34545942 DOI: 10.1111/evo.14358] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 08/17/2021] [Accepted: 08/27/2021] [Indexed: 12/14/2022]
Abstract
Selection may favor greater investment into sexual ornaments when opportunities for future reproduction are limited, for example, under high adult mortality. However, predation, a key driver of mortality, typically selects against elaborate sexual ornaments. Here, we examine the evolution of sexual ornaments in killifishes, which have marked contrasts in life-history strategy among species and inhabit environments that differ in accessibility to aquatic predators. We first assessed if the size of sexual ornaments (unpaired fins) influenced swimming performance. Second, we investigated whether the evolution of larger ornamental fins is driven primarily by the pace of life-history (investment into current vs. future reproduction) or habitat type (a proxy for predation risk). We found that larger fins negatively affected swimming performance. Further, males from species inhabiting ephemeral habitats, with lower predation risk, had larger fins and greater sexual dimorphism in fin size, compared to males from more accessible permanent habitats. We show that enlarged ornamental fins, which impair locomotion, evolve more frequently in environments that are less accessible to predators, without clear associations to life-history strategy. Our results provide a rare link between the evolution of sexual ornaments, effects on locomotion performance, and natural selection on ornament size potentially through habitat differences in predation risk.
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Affiliation(s)
- Will Sowersby
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden.,Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Simon Eckerström-Liedholm
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden.,Wild Animal Initiative, Washington, D.C., 20010
| | - Piotr K Rowiński
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden
| | - Julia Balogh
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden
| | - Stefan Eiler
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden
| | - Joseph D Upstone
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden
| | - Alejandro Gonzalez-Voyer
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden.,Instituto de Ecología, Universidad Nacional Autónoma de México, México City, 04510, Mexico
| | - Björn Rogell
- Department of Zoology, Stockholm University, Stockholm, SE-11418, Sweden.,Department of Aquatic Resources, Institute of Freshwater Research, Swedish University of Agricultural Sciences, Drottningholm, SE-17893, Sweden
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42
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Bocedi G. Ecological sexual dimorphism is modulated by the spatial scale of intersexual resource competition. J Anim Ecol 2021; 90:1810-1813. [PMID: 34346069 DOI: 10.1111/1365-2656.13556] [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: 06/08/2021] [Accepted: 06/16/2021] [Indexed: 12/01/2022]
Abstract
In Focus: Li, X-Y., & H. Kokko. (2021). Sexual dimorphism driven by intersexual resource competition: Why is it rare, and where to look for it? Journal of Animal Ecology, 00, 1-13. Ecological sexual dimorphism, that is differences between the sexes in traits that are naturally selected as opposed to sexually selected, is gaining increasing attention after having often been dismissed as the 'less-parsimonious' explanation for differences between sexes. One potential driver of ecological sexual dimorphism is intersexual resource competition, in a process analogous to ecological character displacement between species; yet, clear empirical examples are scarce. Li and Kokko present mathematical models that introduce novel pieces to the puzzle: the role of the scale of mating competition and the spatial variation in resource availability. They show that ecological sexual dimorphism evolves when local mating groups are small (e.g. monogamous pairs) and when different resources are homogeneously available across habitats. Counterintuitively, larger mating groups (e.g. polygyny), and consequently higher intralocus sexual conflict, lead to sexual monomorphism. Habitat heterogeneity also leads to overlapping niches, although it can sometimes drive polymorphism within sexes. This study highlights why the conditions for intrasexual resource competition to drive evolution of sexual dimorphism are stringent, even in the absence of genetic constraints or competing species. Crucially, it highlights the importance of considering the mating system and the spatial scale of resource competition for understanding the occurrence of ecological sexual dimorphism, showing a large potential for future work considering different aspects of species' life histories and spatial dynamics.
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Affiliation(s)
- Greta Bocedi
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
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Kasimatis KR, Abraham A, Ralph PL, Kern AD, Capra JA, Phillips PC. Evaluating human autosomal loci for sexually antagonistic viability selection in two large biobanks. Genetics 2021; 217:1-10. [PMID: 33683357 DOI: 10.1093/genetics/iyaa015] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/15/2020] [Indexed: 12/16/2022] Open
Abstract
Sex and sexual differentiation are pervasive across the tree of life. Because females and males often have substantially different functional requirements, we expect selection to differ between the sexes. Recent studies in diverse species, including humans, suggest that sexually antagonistic viability selection creates allele frequency differences between the sexes at many different loci. However, theory and population-level simulations indicate that sex-specific differences in viability would need to be very large to produce and maintain reported levels of between-sex allelic differentiation. We address this contradiction between theoretical predictions and empirical observations by evaluating evidence for sexually antagonistic viability selection on autosomal loci in humans using the largest cohort to date (UK Biobank, n = 487,999) along with a second large, independent cohort (BioVU, n = 93,864). We performed association tests between genetically ascertained sex and autosomal loci. Although we found dozens of genome-wide significant associations, none replicated across cohorts. Moreover, closer inspection revealed that all associations are likely due to cross-hybridization with sex chromosome regions during genotyping. We report loci with potential for mis-hybridization found on commonly used genotyping platforms that should be carefully considered in future genetic studies of sex-specific differences. Despite being well powered to detect allele frequency differences of up to 0.8% between the sexes, we do not detect clear evidence for this signature of sexually antagonistic viability selection on autosomal variation. These findings suggest a lack of strong ongoing sexually antagonistic viability selection acting on single locus autosomal variation in humans.
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Affiliation(s)
- Katja R Kasimatis
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Abin Abraham
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Peter L Ralph
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Andrew D Kern
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - John A Capra
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
- Bakar Computational Health Sciences Institute, Department of Epidemiology and Biostatistics, University of California, San Francisco, CA 94143, USA
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
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Grieshop K, Maurizio PL, Arnqvist G, Berger D. Selection in males purges the mutation load on female fitness. Evol Lett 2021; 5:328-343. [PMID: 34367659 PMCID: PMC8327962 DOI: 10.1002/evl3.239] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 05/05/2021] [Accepted: 05/10/2021] [Indexed: 11/26/2022] Open
Abstract
Theory predicts that the ability of selection and recombination to purge mutation load is enhanced if selection against deleterious genetic variants operates more strongly in males than females. However, direct empirical support for this tenet is limited, in part because traditional quantitative genetic approaches allow dominance and intermediate-frequency polymorphisms to obscure the effects of the many rare and partially recessive deleterious alleles that make up the main part of a population's mutation load. Here, we exposed the partially recessive genetic load of a population of Callosobruchus maculatus seed beetles via successive generations of inbreeding, and quantified its effects by measuring heterosis-the increase in fitness experienced when masking the effects of deleterious alleles by heterozygosity-in a fully factorial sex-specific diallel cross among 16 inbred strains. Competitive lifetime reproductive success (i.e., fitness) was measured in male and female outcrossed F1s as well as inbred parental "selfs," and we estimated the 4 × 4 male-female inbred-outbred genetic covariance matrix for fitness using Bayesian Markov chain Monte Carlo simulations of a custom-made general linear mixed effects model. We found that heterosis estimated independently in males and females was highly genetically correlated among strains, and that heterosis was strongly negatively genetically correlated to outbred male, but not female, fitness. This suggests that genetic variation for fitness in males, but not in females, reflects the amount of (partially) recessive deleterious alleles segregating at mutation-selection balance in this population. The population's mutation load therefore has greater potential to be purged via selection in males. These findings contribute to our understanding of the prevalence of sexual reproduction in nature and the maintenance of genetic variation in fitness-related traits.
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Affiliation(s)
- Karl Grieshop
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsalaSE‐75236Sweden
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONM5S 3B2Canada
- Department of Molecular BiosciencesThe Wenner‐Gren InstituteStockholm UniversityStockholmSE‐10691Sweden
| | - Paul L. Maurizio
- Section of Genetic Medicine, Department of MedicineUniversity of ChicagoChicagoIllinois60637
| | - Göran Arnqvist
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsalaSE‐75236Sweden
| | - David Berger
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsalaSE‐75236Sweden
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Colicchio JM, Hamm LN, Verdonk HE, Kooyers NJ, Blackman BK. Adaptive and nonadaptive causes of heterogeneity in genetic differentiation across the Mimulus guttatus genome. Mol Ecol 2021; 30:6486-6507. [PMID: 34289200 DOI: 10.1111/mec.16087] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 07/08/2021] [Accepted: 07/19/2021] [Indexed: 11/29/2022]
Abstract
Genetic diversity becomes structured among populations over time due to genetic drift and divergent selection. Although population structure is often treated as a uniform underlying factor, recent resequencing studies of wild populations have demonstrated that diversity in many regions of the genome may be structured quite dissimilar to the genome-wide pattern. Here, we explored the adaptive and nonadaptive causes of such genomic heterogeneity using population-level, whole genome resequencing data obtained from annual Mimulus guttatus individuals collected across a rugged environment landscape. We found substantial variation in how genetic differentiation is structured both within and between chromosomes, although, in contrast to other studies, known inversion polymorphisms appear to serve only minor roles in this heterogeneity. In addition, much of the genome can be clustered into eight among-population genetic differentiation patterns, but only two of these clusters are particularly consistent with patterns of isolation by distance. By performing genotype-environment association analysis, we also identified genomic intervals where local adaptation to specific climate factors has accentuated genetic differentiation among populations, and candidate genes in these windows indicate climate adaptation may proceed through changes affecting specialized metabolism, drought resistance, and development. Finally, by integrating our findings with previous studies, we show that multiple aspects of plant reproductive biology may be common targets of balancing selection and that variants historically involved in climate adaptation among populations have probably also fuelled rapid adaptation to microgeographic environmental variation within sites.
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Affiliation(s)
- Jack M Colicchio
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Lauren N Hamm
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Hannah E Verdonk
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Nicholas J Kooyers
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA.,Department of Biology, University of Virginia, Charlottesville, Virginia, USA.,Department of Biology, University of Louisiana, Lafayette, Lafayette, Louisiana, USA
| | - Benjamin K Blackman
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA.,Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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Abstract
Sexual dimorphism in gene expression is likely to be the underlying source of dimorphism in a variety of traits. Many analyses implicitly make the assumption that dimorphism only evolves when selection favors different phenotypes in the two sexes, although theory makes clear that it can also evolve as an indirect response to other kinds of selection. Furthermore, previous analyses consider the evolution of a single transcript or trait at a time, ignoring the genetic covariance with other transcripts and traits. We first show which aspects of the genetic-variance-covariance matrix, G, affect dimorphism when these assumptions about selection are relaxed. We then reanalyze gene expression data from Drosophila melanogaster with these predictions in mind. Dimorphism of gene expression for individual transcripts shows the signature of both direct selection for dimorphism and indirect responses to selection. To account for the effect of measurement error on evolutionary predictions, we estimated a G matrix for eight linear combinations of expression traits. Sex-specific genetic variances in female- and male-biased transcription, as well as one relatively unbiased combination, were quite unequal, ensuring that most forms of selection on these traits will have large effects on dimorphism. Predictions of response to selection based on the whole G matrix showed that sexually concordant and antagonistic selection are equally capable of changing sexual dimorphism. In addition, the indirect responses of dimorphism due to cross-trait covariances were quite substantial. The assumption that sexual dimorphism in transcription is an adaptation could be incorrect in many specific cases.
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Affiliation(s)
- David Houle
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Changde Cheng
- Department of Integrative Biology, University of Texas, Austin, TX, USA
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Liang T, Meiri S, Shi L. Sexual size dimorphism in lizards: Rensch's rule, reproductive mode, clutch size, and line fitting method effects. Integr Zool 2021; 17:787-803. [PMID: 34216109 DOI: 10.1111/1749-4877.12569] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Rensch's rule relates to a pattern whereby sexual size dimorphism is more female-biased in small-sized species and more male-biased in large-sized ones. We collected literature and museum data on the body size of males and females belonging to 4032 lizard species, as well as data on their reproductive modes and clutch sizes. We used phylogenetic comparative analyses, and general linear mixed models, to test Rensch's rule and examined how reproductive mode and clutch size affect sexual size dimorphism. Sexual size dimorphism was independent of clutch size in lizard species with variable clutch sizes and in oviparous lizards. Large litters were associated with female-biased sexual dimorphism in viviparous and in scincomorph lizards. Inference regarding Rensch's rule depended on the analytical method used to identify it. The widely used, but less conservative, reduced major axis regression usually support Rensch's rule while ordinary least squares regressions mostly show isometric relationships. The rule tended to apply more to oviparous than to viviparous lizards. We infer that Rensch's rule is, at best, a weak pattern in lizards. This is especially true in viviparous lineages where females reproduce infrequently and therefore evolve large sizes to maximise fecundity, resulting in female-biased dimorphism.
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Affiliation(s)
- Tao Liang
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China.,College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
| | - Shai Meiri
- School of Zoology & the Steinhardt Museum of Natural History, Tel Aviv University, Tel Aviv, Israel
| | - Lei Shi
- College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China
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Deegan DF, Nigam P, Engel N. Sexual Dimorphism of the Heart: Genetics, Epigenetics, and Development. Front Cardiovasc Med 2021; 8:668252. [PMID: 34124200 PMCID: PMC8189176 DOI: 10.3389/fcvm.2021.668252] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022] Open
Abstract
The democratization of genomic technologies has revealed profound sex biases in expression patterns in every adult tissue, even in organs with no conspicuous differences, such as the heart. With the increasing awareness of the disparities in cardiac pathophysiology between males and females, there are exciting opportunities to explore how sex differences in the heart are established developmentally. Although sexual dimorphism is traditionally attributed to hormonal influence, expression and epigenetic sex biases observed in early cardiac development can only be accounted for by the difference in sex chromosome composition, i.e., XX in females and XY in males. In fact, genes linked to the X and Y chromosomes, many of which encode regulatory factors, are expressed in cardiac progenitor cells and at every subsequent developmental stage. The effect of the sex chromosome composition may explain why many congenital heart defects originating before gonad formation exhibit sex biases in presentation, mortality, and morbidity. Some transcriptional and epigenetic sex biases established soon after fertilization persist in cardiac lineages, suggesting that early epigenetic events are perpetuated beyond early embryogenesis. Importantly, when sex hormones begin to circulate, they encounter a cardiac genome that is already functionally distinct between the sexes. Although there is a wealth of knowledge on the effects of sex hormones on cardiac function, we propose that sex chromosome-linked genes and their downstream targets also contribute to the differences between male and female hearts. Moreover, identifying how hormones influence sex chromosome effects, whether antagonistically or synergistically, will enhance our understanding of how sex disparities are established. We also explore the possibility that sexual dimorphism of the developing heart predicts sex-specific responses to environmental signals and foreshadows sex-biased health-related outcomes after birth.
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Affiliation(s)
- Daniel F Deegan
- Lewis Katz School of Medicine, Fels Institute for Cancer Research, Temple University, Philadelphia, PA, United States
| | - Priya Nigam
- Lewis Katz School of Medicine, Fels Institute for Cancer Research, Temple University, Philadelphia, PA, United States
| | - Nora Engel
- Lewis Katz School of Medicine, Fels Institute for Cancer Research, Temple University, Philadelphia, PA, United States
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Curlis JD, Cox CL, Cox RM. Sex-Specific Population Differences in Resting Metabolism Are Associated with Intraspecific Variation in Sexual Size Dimorphism of Brown Anoles. Physiol Biochem Zool 2021; 94:205-214. [PMID: 33970831 DOI: 10.1086/714638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractSexual size dimorphism can vary in direction and magnitude across populations, but the extent to which such intraspecific variation is associated with sex and population differences in underlying metabolic processes is unclear. We compared resting metabolic rates (RMRs) of brown anole lizards (Anolis sagrei) from two island populations in the Bahamas (Eleuthera and Great Exuma) that differ in the magnitude of male-biased sexual size dimorphism. Whereas females from each population exhibit similar growth rates and body sizes, males from Great Exuma grow more quickly and attain larger body sizes than males from Eleuthera. We found that these population differences in growth of males persisted in captivity. Therefore, we predicted that males from each population would differ in RMR, whereas females would not. Consistent with this prediction, we found that RMR of males from Eleuthera was higher than that of males from Great Exuma, particularly at higher temperatures. As predicted, RMR of females did not differ between populations. Despite this apparent sex-specific trade-off between growth rate and RMR at the population level, we found a positive relationship between growth rate and RMR at the individual level. The fact that Great Exuma males maintain lower RMR than Eleuthera males, despite their greater absolute growth rates and the positive relationship between RMR and growth rate across individuals, suggests that Great Exuma males may have lower baseline metabolic demands and/or greater growth efficiency than Eleuthera males. Our results call attention to sex-specific divergence in metabolism as a potential mechanism for intraspecific divergence in sexual size dimorphism.
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Liotta MN, Abbott JK, Morris MR, Rios‐Cardenas O. Antagonistic selection on body size and sword length in a wild population of the swordtail fish, Xiphophorus multilineatus: Potential for intralocus tactical conflict. Ecol Evol 2021; 11:3941-3955. [PMID: 33976786 PMCID: PMC8093718 DOI: 10.1002/ece3.7288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/08/2021] [Accepted: 01/18/2021] [Indexed: 11/06/2022] Open
Abstract
Alternative reproductive tactics (ARTs) have provided valuable insights into how sexual selection and life history trade-offs can lead to variation within a sex. However, the possibility that tactics may constrain evolution through intralocus tactical conflict (IATC) is rarely considered. In addition, when IATC has been considered, the focus has often been on the genetic correlations between the ARTs, while evidence that the ARTs have different optima for associated traits and that at least one of the tactics is not at its optimum is often missing. Here, we investigate selection on three traits associated with the ARTs in the swordtail fish Xiphophorus multilineatus; body size, body shape, and the sexually selected trait for which these fishes were named, sword length (elongation of the caudal fin). All three traits are tactically dimorphic, with courter males being larger, deeper bodied and having longer swords, and the sneaker males being smaller, more fusiform and having shorter swords. Using measures of reproductive success in a wild population we calculated selection differentials, as well as linear and quadratic gradients. We demonstrated that the tactics have different optima and at least one of the tactics is not at its optimum for body size and sword length. Our results provide the first evidence of selection in the wild on the sword, an iconic trait for sexual selection. In addition, given the high probability that these traits are genetically correlated to some extent between the two tactics, our study suggests that IATC is constraining both body size and the sword from reaching their phenotypic optima. We discuss the importance of considering the role of IATC in the evolution of tactical dimorphism, how this conflict can be present despite tactical dimorphism, and how it is important to consider this conflict when explaining not only variation within a species but differences across species as well.
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Affiliation(s)
- Melissa N. Liotta
- Department of Biological SciencesThe Ohio Center for Ecological and Evolutionary StudiesOhio UniversityAthensOHUSA
| | | | - Molly R. Morris
- Department of Biological SciencesThe Ohio Center for Ecological and Evolutionary StudiesOhio UniversityAthensOHUSA
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