1
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Against the Odds: Hybrid Zones between Mangrove Killifish Species with Different Mating Systems. Genes (Basel) 2021; 12:genes12101486. [PMID: 34680881 PMCID: PMC8535463 DOI: 10.3390/genes12101486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 11/16/2022] Open
Abstract
Different mating systems are expected to affect the extent and direction of hybridization. Due to the different levels of sexual conflict, the weak inbreeder/strong outbreeder (WISO) hypothesis predicts that gametes from self-incompatible (SI) species should outcompete gametes from self-compatible (SC) ones. However, other factors such as timing of selfing and unilateral incompatibilities may also play a role on the direction of hybridization. In addition, differential mating opportunities provided by different mating systems are also expected to affect the direction of introgression in hybrid zones involving outcrossers and selfers. Here, we explored these hypotheses with a unique case of recent hybridization between two mangrove killifish species with different mating systems, Kryptolebias ocellatus (obligately outcrossing) and K. hermaphroditus (predominantly self-fertilizing) in two hybrid zones in southeast Brazil. Hybridization rates were relatively high (~20%), representing the first example of natural hybridization between species with different mating systems in vertebrates. All F1 individuals were sired by the selfing species. Backcrossing was small, but mostly asymmetrical with the SI parental species, suggesting pattern commonly observed in plant hybrid zones with different mating systems. Our findings shed light on how contrasting mating systems may affect the direction and extent of gene flow between sympatric species, ultimately affecting the evolution and maintenance of hybrid zones.
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2
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Cramer ERA, Grønstøl G, Maxwell L, Kovach AI, Lifjeld JT. Sperm length divergence as a potential prezygotic barrier in a passerine hybrid zone. Ecol Evol 2021; 11:9489-9497. [PMID: 34306637 PMCID: PMC8293778 DOI: 10.1002/ece3.7768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 11/09/2022] Open
Abstract
The saltmarsh sparrow Ammospiza caudacuta and Nelson's sparrow A. nelsoni differ in ecological niche, mating behavior, and plumage, but they hybridize where their breeding distributions overlap. In this advanced hybrid zone, past interbreeding and current backcrossing result in substantial genomic introgression in both directions, although few hybrids are currently produced in most locations. However, because both species are nonterritorial and have only brief male-female interactions, it is difficult to determine to what extent assortative mating explains the low frequency of hybrid offspring. Since females often copulate with multiple males, a role of sperm as a postcopulatory prezygotic barrier appears plausible. Here, we show that sperm length differs between the two species in the hybrid zone, with low among-male variation consistent with strong postcopulatory sexual selection on sperm cells. We hypothesize that divergence in sperm length may constitute a reproductive barrier between species, as sperm length co-evolves with the size of specialized female sperm storage tubules. Sperm does not appear to act as a postzygotic barrier, as sperm from hybrids was unexceptional.
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Affiliation(s)
| | | | - Logan Maxwell
- Natural Resources and the EnvironmentUniversity of New HampshireDurhamNHUSA
| | - Adrienne I. Kovach
- Natural Resources and the EnvironmentUniversity of New HampshireDurhamNHUSA
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3
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Izquierdo-Rico MJ, Moros-Nicolás C, Pérez-Crespo M, Laguna-Barraza R, Gutiérrez-Adán A, Veyrunes F, Ballesta J, Laudet V, Chevret P, Avilés M. ZP4 Is Present in Murine Zona Pellucida and Is Not Responsible for the Specific Gamete Interaction. Front Cell Dev Biol 2021; 8:626679. [PMID: 33537315 PMCID: PMC7848090 DOI: 10.3389/fcell.2020.626679] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
Mammalian eggs are surrounded by an extracellular matrix called the zona pellucida (ZP). This envelope participates in processes such as acrosome reaction induction, sperm binding, protection of the oviductal embryo, and may be involved in speciation. In eutherian mammals, this coat is formed of three or four glycoproteins (ZP1-ZP4). While Mus musculus has been used as a model to study the ZP for more than 35 years, surprisingly, it is the only eutherian species in which the ZP is formed of three glycoproteins Zp1, Zp2, and Zp3, Zp4 being a pseudogene. Zp4 was lost in the Mus lineage after it diverged from Rattus, although it is not known when precisely this loss occurred. In this work, the status of Zp4 in several murine rodents was tested by phylogenetic, molecular, and proteomic analyses. Additionally, assays of cross in vitro fertilization between three and four ZP rodents were performed to test the effect of the presence of Zp4 in murine ZP and its possible involvement in reproductive isolation. Our results showed that Zp4 pseudogenization is restricted to the subgenus Mus, which diverged around 6 MYA. Heterologous in vitro fertilization assays demonstrate that a ZP formed of four glycoproteins is not a barrier for the spermatozoa of species with a ZP formed of three glycoproteins. This study identifies the existence of several mouse species with four ZPs that can be considered suitable for use as an experimental animal model to understand the structural and functional roles of the four ZP proteins in other species, including human.
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Affiliation(s)
- Mª José Izquierdo-Rico
- Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Murcia, Spain
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), Murcia, Spain
- International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, Murcia, Spain
| | - Carla Moros-Nicolás
- Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Murcia, Spain
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), Murcia, Spain
- International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, Murcia, Spain
| | - Míriam Pérez-Crespo
- Department of Animal Reproduction, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Madrid, Spain
| | - Ricardo Laguna-Barraza
- Department of Animal Reproduction, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Madrid, Spain
| | - Alfonso Gutiérrez-Adán
- Department of Animal Reproduction, Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Madrid, Spain
| | - Frédéric Veyrunes
- Institut des Sciences de l'Evolution, UMR5554 CNRS/Université Montpellier/IRD/EPHE, Montpellier, France
| | - José Ballesta
- Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Murcia, Spain
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), Murcia, Spain
- International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, Murcia, Spain
| | - Vincent Laudet
- Marine Eco-Evo-Devo Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Pascale Chevret
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, CNRS, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Manuel Avilés
- Department of Cell Biology and Histology, Faculty of Medicine, University of Murcia, Murcia, Spain
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), Murcia, Spain
- International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, Murcia, Spain
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4
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Roldan ERS, Teves ME. Understanding sperm physiology: Proximate and evolutionary explanations of sperm diversity. Mol Cell Endocrinol 2020; 518:110980. [PMID: 32853744 DOI: 10.1016/j.mce.2020.110980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/19/2022]
Abstract
Much can be gained from the comprehensive study of a biological system. Based on what is known as Mayr's proximate-ultimate causation and the subsequent expansion to Tinbergen's four questions, biological traits can be understood by taking into account different approximations that try to explain mechanisms, development, adaptive significance or phylogeny. These, in principle, separate areas, can be integrated crossing boundaries, but bearing in mind that answers to one question would not explain a different query. Studies of sperm biology have, until now, not benefited much from this framework and potential integration. Proximate causes (particularly mechanisms) have been the subject of interest for reproductive biologists, and evolutionary explanations have been the domain of behavioural ecologists with interest in adaptive significance of traits in the context of post-copulatory sexual selection. This review will summarize opportunities for research in the different areas, focusing on sperm preparation for fertilization and suggesting possible integration within and between proximate and evolutionary studies.
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Affiliation(s)
- Eduardo R S Roldan
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain.
| | - Maria Eugenia Teves
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, VA, USA.
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5
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Firman RC. Of mice and women: advances in mammalian sperm competition with a focus on the female perspective. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200082. [PMID: 33070720 DOI: 10.1098/rstb.2020.0082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although initially lagging behind discoveries being made in other taxa, mammalian sperm competition is now a productive and advancing field of research. Sperm competition in mammals is not merely a 'sprint-race' between the gametes of rival males, but rather a race over hurdles; those hurdles being the anatomical and physiological barriers provided by the female reproductive tract, as well as the egg and its vestments. With this in mind, in this review, I discuss progress in the field while focusing on the female perspective. I highlight ways by which sperm competition can have positive effects on female reproductive success and discuss how competitive outcomes are not only owing to dynamics between the ejaculates of rival males, but also attributable to mechanisms by which female mammals bias paternity toward favourable sires. Drawing on examples across different species-from mice to humans-I provide an overview of the accumulated evidence which firmly establishes that sperm competition is a key selective force in the evolution of male traits and detail how females can respond to increased sperm competitiveness with increased egg resistance to fertilization. I also discuss evidence for facultative responses to the sperm competition environment observed within mammal species. Overall, this review identifies shortcomings in our understanding of the specific mechanisms by which female mammals 'select' sperm. More generally, this review demonstrates how, moving forward, mammals will continue to be effective animal models for studying both evolutionary and facultative responses to sperm competition. This article is part of the theme issue 'Fifty years of sperm competition'.
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Affiliation(s)
- Renée C Firman
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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6
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Garlovsky MD, Yusuf LH, Ritchie MG, Snook RR. Within-population sperm competition intensity does not predict asymmetry in conpopulation sperm precedence. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200071. [PMID: 33070721 PMCID: PMC7661444 DOI: 10.1098/rstb.2020.0071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Postcopulatory sexual selection can generate evolutionary arms races between the sexes resulting in the rapid coevolution of reproductive phenotypes. As traits affecting fertilization success diverge between populations, postmating prezygotic (PMPZ) barriers to gene flow may evolve. Conspecific sperm precedence is a form of PMPZ isolation thought to evolve early during speciation yet has mostly been studied between species. Here, we show conpopulation sperm precedence (CpSP) between Drosophila montana populations. Using Pool-seq genomic data we estimate divergence times and ask whether PMPZ isolation evolved in the face of gene flow. We find models incorporating gene flow fit the data best indicating populations experienced considerable gene flow during divergence. We find CpSP is asymmetric and mirrors asymmetry in non-competitive PMPZ isolation, suggesting these phenomena have a shared mechanism. However, we show asymmetry is unrelated to the strength of postcopulatory sexual selection acting within populations. We tested whether overlapping foreign and coevolved ejaculates within the female reproductive tract altered fertilization success but found no effect. Our results show that neither time since divergence nor sperm competitiveness predicts the strength of PMPZ isolation. We suggest that instead cryptic female choice or mutation-order divergence may drive divergence of postcopulatory phenotypes resulting in PMPZ isolation. This article is part of the theme issue ‘Fifty years of sperm competition’.
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Affiliation(s)
- Martin D Garlovsky
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Leeban H Yusuf
- Centre for Biological Diversity, University of St Andrews, St Andrews KY16 9TH, UK
| | - Michael G Ritchie
- Centre for Biological Diversity, University of St Andrews, St Andrews KY16 9TH, UK
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Stockholm 106-91, Sweden
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7
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Tourmente M, Varea-Sánchez M, Roldan ERS. Faster and more efficient swimming: energy consumption of murine spermatozoa under sperm competition†. Biol Reprod 2020; 100:420-428. [PMID: 30203065 DOI: 10.1093/biolre/ioy197] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 06/22/2018] [Accepted: 09/08/2018] [Indexed: 11/14/2022] Open
Abstract
ATP supply is essential for sperm performance and increases in ATP content coevolve with enhanced sperm swimming velocity as a response to sperm competition in rodents. ATP content is the balance between production and consumption but, although ATP production has received much attention, little is known about ATP consumption. The rate of ATP consumption is crucial for the propagation of the flagellar wave, becoming a main determinant of the time and distance sperm could move before exhausting their reserves. A high yield in distance per unit of ATP consumed (efficiency) could provide advantages in sperm competition. We characterized sperm ATP consumption rate in a group of mouse species with different sperm competition levels to understand its impact on swimming velocity, duration, and yield of sperm ATP reserves. Interspecific comparisons revealed that sperm of species with higher sperm competition levels had high ATP consumption rates and faster swimming velocity. Moreover, sperm that consumed ATP at a faster rate swam more efficiently, since they were able to cover more distance per unit of ATP consumed. Our results suggest that by coupling the advantages of higher ATP turnover rates to increased efficiency of ATP expenditure, sperm would respond to increasingly competitive environments while maintaining a positive ATP balance.
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Affiliation(s)
- Maximiliano Tourmente
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, Madrid, Spain
- College of Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - María Varea-Sánchez
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, Madrid, Spain
| | - Eduardo R S Roldan
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, Madrid, Spain
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8
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Roldan ERS. Sperm competition and the evolution of sperm form and function in mammals. Reprod Domest Anim 2019; 54 Suppl 4:14-21. [DOI: 10.1111/rda.13552] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Eduardo R. S. Roldan
- Department of Biodiversity and Evolutionary Biology; Museo Nacional de Ciencias Naturales (CSIC); Madrid Spain
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9
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Civetta A, Ranz JM. Genetic Factors Influencing Sperm Competition. Front Genet 2019; 10:820. [PMID: 31572439 PMCID: PMC6753916 DOI: 10.3389/fgene.2019.00820] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 08/08/2019] [Indexed: 12/26/2022] Open
Abstract
Females of many different species often mate with multiple males, creating opportunities for competition among their sperm. Although originally unappreciated, sperm competition is now considered a central form of post-copulatory male–male competition that biases fertilization. Assays of differences in sperm competitive ability between males, and interactions between females and males, have made it possible to infer some of the main mechanisms of sperm competition. Nevertheless, classical genetic approaches have encountered difficulties in identifying loci influencing sperm competitiveness while functional and comparative genomic methodologies, as well as genetic variant association studies, have uncovered some interesting candidate genes. We highlight how the systematic implementation of approaches that incorporate gene perturbation assays in experimental competitive settings, together with the monitoring of progeny output or sperm features and behavior, has allowed the identification of genes unambiguously linked to sperm competitiveness. The emerging portrait from 45 genes (33 from fruit flies, 8 from rodents, 2 from nematodes, and 2 from ants) is their remarkable breadth of biological roles exerted through males and females, the non-preponderance of sperm genes, and their overall pleiotropic nature.
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Affiliation(s)
- Alberto Civetta
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada
| | - José M Ranz
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, United States
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10
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Quantification of Reproductive Isolating Barriers Between Two Naturally Hybridizing Killifish Species. Evol Biol 2018. [DOI: 10.1007/s11692-018-9460-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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11
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Firman RC. Postmating sexual conflict and female control over fertilization during gamete interaction. Ann N Y Acad Sci 2018. [DOI: 10.1111/nyas.13635] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Renée C. Firman
- Centre for Evolutionary Biology University of Western Australia Western Australia Australia
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12
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Delbarco-Trillo J, Tourmente M, Varea-Sánchez M, Roldan ERS. Is male reproductive senescence minimized in Mus species with high levels of sperm competition? Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Vicens A, Borziak K, Karr TL, Roldan ERS, Dorus S. Comparative Sperm Proteomics in Mouse Species with Divergent Mating Systems. Mol Biol Evol 2017; 34:1403-1416. [PMID: 28333336 PMCID: PMC5435083 DOI: 10.1093/molbev/msx084] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sexual selection is the pervasive force underlying the dramatic divergence of sperm form and function. Although it has been demonstrated that testis gene expression evolves rapidly, exploration of the proteomic basis of sperm diversity is in its infancy. We have employed a whole-cell proteomics approach to characterize sperm divergence among closely related Mus species that experience different sperm competition regimes and exhibit pronounced variation in sperm energetics, motility and fertilization capacity. Interspecific comparisons revealed significant abundance differences amongst proteins involved in fertilization capacity, including those that govern sperm-zona pellucida interactions, axoneme components and metabolic proteins. Ancestral reconstruction of relative testis size suggests that the reduction of zona pellucida binding proteins and heavy-chain dyneins was associated with a relaxation in sperm competition in the M. musculus lineage. Additionally, the decreased reliance on ATP derived from glycolysis in high sperm competition species was reflected in abundance decreases in glycolytic proteins of the principle piece in M. spretus and M. spicilegus. Comparison of protein abundance and stage-specific testis expression revealed a significant correlation during spermatid development when dynamic morphological changes occur. Proteins underlying sperm diversification were also more likely to be subject to translational repression, suggesting that sperm composition is influenced by the evolution of translation control mechanisms. The identification of functionally coherent classes of proteins relating to sperm competition highlights the utility of evolutionary proteomic analyses and reveals that both intensified and relaxed sperm competition can have a pronounced impact on the molecular composition of the male gamete.
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Affiliation(s)
- Alberto Vicens
- Reproductive Biology and Evolution Group, Department of Biodiversity and Biological Evolution, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - Kirill Borziak
- Department of Biology, Syracuse University, Syracuse, NY
| | - Timothy L Karr
- Department of Genomics and Genetic Resources, Kyoto Institute of Technology, Kyoto, Japan
| | - Eduardo R S Roldan
- Reproductive Biology and Evolution Group, Department of Biodiversity and Biological Evolution, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - Steve Dorus
- Department of Biology, Syracuse University, Syracuse, NY
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14
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Moran PA, Ritchie MG, Bailey NW. A rare exception to Haldane's rule: Are X chromosomes key to hybrid incompatibilities? Heredity (Edinb) 2017; 118:554-562. [PMID: 28098850 PMCID: PMC5436020 DOI: 10.1038/hdy.2016.127] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 12/27/2022] Open
Abstract
The prevalence of Haldane's rule suggests that sex chromosomes commonly have a key role in reproductive barriers and speciation. However, the majority of research on Haldane's rule has been conducted in species with conventional sex determination systems (XY and ZW) and exceptions to the rule have been understudied. Here we test the role of X-linked incompatibilities in a rare exception to Haldane's rule for female sterility in field cricket sister species (Teleogryllus oceanicus and T. commodus). Both have an XO sex determination system. Using three generations of crosses, we introgressed X chromosomes from each species onto different, mixed genomic backgrounds to test predictions about the fertility and viability of each cross type. We predicted that females with two different species X chromosomes would suffer reduced fertility and viability compared with females with two parental X chromosomes. However, we found no strong support for such X-linked incompatibilities. Our results preclude X-X incompatibilities and instead support an interchromosomal epistatic basis to hybrid female sterility. We discuss the broader implications of these findings, principally whether deviations from Haldane's rule might be more prevalent in species without dimorphic sex chromosomes.
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Affiliation(s)
- P A Moran
- Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews, Fife, UK
| | - M G Ritchie
- Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews, Fife, UK
| | - N W Bailey
- Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews, Fife, UK
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15
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Brothers AN, Delph LF. Divergence in style length and pollen size leads to a postmating-prezygotic reproductive barrier among populations of Silene latifolia. Evolution 2017; 71:1532-1540. [PMID: 28394403 DOI: 10.1111/evo.13248] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 03/27/2017] [Indexed: 12/25/2022]
Abstract
A central tenet of speciation research is the need to identify reproductive isolating barriers. One approach to this line of research is to identify the phenotypes that lead to reproductive isolation. Several studies on flowering plants have shown that differences in style length contribute to reproductive isolation between species, leading us to consider whether style length could act as a reproductive barrier among populations of a single species. This could occur if style length varied sufficiently and pollen size covaried with style length. Populations of Silene latifolia exhibit variation in flower size, including style length, that is negatively correlated with annual precipitation. We show that this divergence in style length has a genetic basis and acts as a reproductive barrier: males from small-flowered populations produced relatively small pollen grains that were poor at fertilizing ovules when crossed to females from large-flowered populations, leading to a significant reduction in seed production. Manipulating the distance pollen tubes had to travel revealed that this failure was purely mechanical and not the result of other incompatibilities. These results show that style length acts as a postmating-prezygotic reproductive barrier and indicate a potential link between ecotypic differentiation and reproductive isolation within a species.
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Affiliation(s)
- Amanda N Brothers
- Department of Biology, Indiana University, Bloomington, Indiana, 47405
| | - Lynda F Delph
- Department of Biology, Indiana University, Bloomington, Indiana, 47405
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16
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Postmating Female Control: 20 Years of Cryptic Female Choice. Trends Ecol Evol 2017; 32:368-382. [PMID: 28318651 PMCID: PMC5511330 DOI: 10.1016/j.tree.2017.02.010] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 12/22/2022]
Abstract
Cryptic female choice (CFC) represents postmating intersexual selection arising from female-driven mechanisms at or after mating that bias sperm use and impact male paternity share. Although biologists began to study CFC relatively late, largely spurred by Eberhard's book published 20 years ago, the field has grown rapidly since then. Here, we review empirical progress to show that numerous female processes offer potential for CFC, from mating through to fertilization, although seldom has CFC been clearly demonstrated. We then evaluate functional implications, and argue that, under some conditions, CFC might have repercussions for female fitness, sexual conflict, and intersexual coevolution, with ramifications for related evolutionary phenomena, such as speciation. We conclude by identifying directions for future research in this rapidly growing field.
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17
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Cramer ERA, Ålund M, McFarlane SE, Johnsen A, Qvarnström A. Females discriminate against heterospecific sperm in a natural hybrid zone. Evolution 2016; 70:1844-55. [DOI: 10.1111/evo.12986] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 05/22/2016] [Accepted: 06/01/2016] [Indexed: 01/15/2023]
Affiliation(s)
- Emily R. A. Cramer
- Natural History Museum; University of Oslo; 0318 Oslo Norway
- Current Address: Smithsonian Migratory Bird Center; PO Box 37012 MRC5503, Washington, District of Columbia 20008, and Cornell Lab of Ornithology Ithaca New York 14850
| | - Murielle Ålund
- Department of Ecology and Genetics; Animal Ecology, Uppsala University; Uppsala 75236 Sweden
| | - S. Eryn McFarlane
- Department of Ecology and Genetics; Animal Ecology, Uppsala University; Uppsala 75236 Sweden
| | - Arild Johnsen
- Natural History Museum; University of Oslo; 0318 Oslo Norway
| | - Anna Qvarnström
- Department of Ecology and Genetics; Animal Ecology, Uppsala University; Uppsala 75236 Sweden
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18
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19
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Firman RC, Simmons LW. Gametic interactions promote inbreeding avoidance in house mice. Ecol Lett 2015; 18:937-43. [DOI: 10.1111/ele.12471] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 05/27/2015] [Indexed: 02/05/2023]
Affiliation(s)
- Renée C. Firman
- Centre for Evolutionary Biology; School of Animal Biology; M092; The University of Western Australia; Nedlands WA 6009 Australia
| | - Leigh W. Simmons
- Centre for Evolutionary Biology; School of Animal Biology; M092; The University of Western Australia; Nedlands WA 6009 Australia
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20
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Firman RC, Simmons LW. No evidence of conpopulation sperm precedence between allopatric populations of house mice. PLoS One 2014; 9:e107472. [PMID: 25295521 PMCID: PMC4189782 DOI: 10.1371/journal.pone.0107472] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 08/16/2014] [Indexed: 01/12/2023] Open
Abstract
Investigations into the evolution of reproductive barriers have traditionally focused on closely related species, and the prevalence of conspecific sperm precedence. The effectiveness of conspecific sperm precedence at limiting gene exchange between species suggests that gametic isolation is an important component of reproductive isolation. However, there is a paucity of tests for evidence of sperm precedence during the earlier stages of divergence, for example among isolated populations. Here, we sourced individuals from two allopatric populations of house mice (Mus domesticus) and performed competitive in vitro fertilisation assays to test for conpopulation sperm precedence specifically at the gametic level. We found that ova population origin did not influence the outcome of the sperm competitions, and thus provide no evidence of conpopulation or heteropopulation sperm precedence. Instead, we found that males from a population that had evolved under a high level of postcopulatory sexual selection consistently outcompeted males from a population that had evolved under a relatively lower level of postcopulatory sexual selection. We standardised the number of motile sperm of each competitor across the replicate assays. Our data therefore show that competitive fertilizing success was directly attributable to differences in sperm fertilizing competence.
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Affiliation(s)
- Renée C. Firman
- Centre for Evolutionary Biology, University of Western Australia, Nedlands, Western Australia, Australia
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, University of Western Australia, Nedlands, Western Australia, Australia
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Dey A, Jin Q, Chen YC, Cutter AD. Gonad morphogenesis defects drive hybrid male sterility in asymmetric hybrid breakdown of Caenorhabditis nematodes. Evol Dev 2014; 16:362-72. [PMID: 25196892 DOI: 10.1111/ede.12097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Determining the causes and evolution of reproductive barriers to gene flow between populations, speciation, is the key to understanding the origin of diversity in nature. Many species manifest hybrid breakdown when they intercross, characterized by increasingly exacerbated problems in later generations of hybrids. Recently, Caenorhabditis nematodes have emerged as a genetic model for studying speciation, and here we investigate the nature and causes of hybrid breakdown between Caenorhabditis remanei and C. latens. We quantify partial F1 hybrid inviability and extensive F2 hybrid inviability; the ~75% F2 embryonic arrest occurs primarily during gastrulation or embryonic elongation. Moreover, F1 hybrid males exhibit Haldane's rule asymmetrically for both sterility and inviability, being strongest when C. remanei serves as maternal parent. We show that the mechanism by which sterile hybrid males are incapable of transferring sperm or a copulatory plug involves defective gonad morphogenesis, which we hypothesize results from linker cell defects in migration and/or cell death during development. This first documented case of partial hybrid male sterility in Caenorhabditis follows expectations of Darwin's corollary to Haldane's rule for asymmetric male fitness, providing a powerful foundation for molecular dissection of intrinsic reproductive barriers and divergence of genetic pathways controlling organ morphogenesis.
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Affiliation(s)
- Alivia Dey
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada, M5S 3B2
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22
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Ting JJ, Woodruff GC, Leung G, Shin NR, Cutter AD, Haag ES. Intense sperm-mediated sexual conflict promotes reproductive isolation in Caenorhabditis nematodes. PLoS Biol 2014; 12:e1001915. [PMID: 25072732 PMCID: PMC4114750 DOI: 10.1371/journal.pbio.1001915] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 06/19/2014] [Indexed: 01/08/2023] Open
Abstract
Sperm from other species invade female tissues to cause sterility and death, helping to keep nematode species boundaries intact. Conflict between the sexes over reproductive interests can drive rapid evolution of reproductive traits and promote speciation. Here we show that inter-species mating between Caenorhabditis nematodes sterilizes maternal individuals. The principal effectors of male-induced harm are sperm cells, which induce sterility and shorten lifespan by displacing conspecific sperm, invading the ovary, and sometimes breaching the gonad to infiltrate other tissues. This sperm-mediated harm is pervasive across species, but idiosyncrasies in its magnitude implicate both independent histories of sexually antagonistic coevolution within species and differences in reproductive mode (self-fertilizing hermaphrodites versus females) in determining its severity. Consistent with this conclusion, in androdioecious species the hermaphrodites are more vulnerable, the males more benign, or both. Patterns of assortative mating and a low incidence of invasive sperm occurring with conspecific mating are indicative of ongoing intra-specific sexual conflict that results in inter-species reproductive incompatibility. The sexes have divergent reproductive interests, and conflict arising from this disparity can drive the rapid evolution of reproductive traits and promote speciation. Here we describe a unique reproductive barrier in Caenorhabditis nematodes that is induced by sperm. We found that mating between species can sterilize maternal worms and even cause premature death, and we were able to attribute this phenomenon directly to the sperm themselves. Sperm from other species can displace sperm from the same species and, in some cases, can invade inappropriate parts of the maternal reproductive system and even their non-reproductive tissues. We find that mating to males of another species harms females far more than does within-species mating. Overall, our observations are consistent with ongoing sexual conflict between the sexes within species, arising as a byproduct of sperm competition among the gametes of different males. Finally, patterns of assortative mating indicate that mating behaviours that reduce the likelihood of costly inter-species mating have evolved in this group of animals. These findings support an important role of sexual selection and gametic interactions contributing to reproductive boundaries between species, as predicted by evolutionary theory.
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Affiliation(s)
- Janice J. Ting
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Gavin C. Woodruff
- Department of Biology, University of Maryland, College Park, Maryland, United States of America
| | - Gemma Leung
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Na-Ra Shin
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Asher D. Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail: (ADC); (ESH)
| | - Eric S. Haag
- Department of Biology, University of Maryland, College Park, Maryland, United States of America
- * E-mail: (ADC); (ESH)
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23
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Firman RC, Gomendio M, Roldan ERS, Simmons LW. The Coevolution of Ova Defensiveness with Sperm Competitiveness in House Mice. Am Nat 2014; 183:565-72. [DOI: 10.1086/675395] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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24
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Engqvist L, Cordes N, Schwenniger J, Bakhtina S, Schmoll T. Female Remating Behavior in a Lekking Moth. Ethology 2014. [DOI: 10.1111/eth.12237] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Leif Engqvist
- Evolutionary Biology; Bielefeld University; Bielefeld Germany
| | - Nils Cordes
- Evolutionary Biology; Bielefeld University; Bielefeld Germany
| | | | | | - Tim Schmoll
- Evolutionary Biology; Bielefeld University; Bielefeld Germany
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25
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Vicens A, Lüke L, Roldan ERS. Proteins involved in motility and sperm-egg interaction evolve more rapidly in mouse spermatozoa. PLoS One 2014; 9:e91302. [PMID: 24608277 PMCID: PMC3948348 DOI: 10.1371/journal.pone.0091302] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/08/2014] [Indexed: 02/03/2023] Open
Abstract
Proteomic studies of spermatozoa have identified a large catalog of integral sperm proteins. Rapid evolution of these proteins may underlie adaptive changes of sperm traits involved in different events leading to fertilization, although the selective forces underlying such rapid evolution are not well understood. A variety of selective forces may differentially affect several steps ending in fertilization, thus resulting in a compartmentalized adaptation of sperm proteins. Here we analyzed the evolution of genes associated to various events in the sperm’s life, from sperm formation to sperm-egg interaction. Evolutionary analyses were performed on gene sequences from 17 mouse strains whose genomes have been sequenced. Four of these are derived from wild Mus musculus, M. domesticus, M. castaneus and M. spretus. We found a higher proportion of genes exhibiting a signature of positive selection among those related to sperm motility and sperm-egg interaction. Furthermore, sperm proteins involved in sperm-egg interaction exhibited accelerated evolution in comparison to those involved in other events. Thus, we identified a large set of candidate proteins for future comparative analyses of genotype-phenotype associations in spermatozoa of species subjected to different sexual selection pressures. Adaptive evolution of proteins involved in motility could be driven by sperm competition, since this selective force is known to increase the proportion of motile sperm and their swimming velocity. On the other hand, sperm proteins involved in gamete interaction could be coevolving with their egg partners through episodes of sexual selection or sexual conflict resulting in species-specific sperm-egg interactions and barriers preventing interspecies fertilization.
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Affiliation(s)
- Alberto Vicens
- Reproductive Ecology and Biology Group, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - Lena Lüke
- Reproductive Ecology and Biology Group, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - Eduardo R. S. Roldan
- Reproductive Ecology and Biology Group, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
- * E-mail:
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26
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27
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Rose EG, Brand CL, Wilkinson GS. Rapid evolution of asymmetric reproductive incompatibilities in stalk-eyed flies. Evolution 2013; 68:384-96. [PMID: 24171729 DOI: 10.1111/evo.12307] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/22/2013] [Indexed: 12/22/2022]
Abstract
The steps by which isolated populations acquire reproductive incompatibilities remain poorly understood. One potentially important process is postcopulatory sexual selection because it can generate divergence between populations in traits that influence fertilization success after copulation. Here we present a comprehensive analysis of this form of reproductive isolation by conducting reciprocal crosses between variably diverged populations of stalk-eyed flies (Teleopsis dalmanni). First, we measure seven types of reproductive incompatibility between copulation and fertilization. We then compare fertilization success to hatching success to quantify hybrid inviability. Finally, we determine if sperm competition acts to reinforce or counteract any incompatibilities. We find evidence for multiple incompatibilities in most crosses, including failure to store sperm after mating, failure of sperm to reach the site of fertilization, failure of sperm to fertilize eggs, and failure of embryos to develop. Local sperm have precedence over foreign sperm, but this effect is due mainly to differences in sperm transfer and reduced hatching success. Crosses between recently diverged populations are asymmetrical with regard to the degree and type of incompatibility. Because sexual conflict in these flies is low, postcopulatory sexual selection, rather than antagonistic coevolution, likely causes incompatibilities due to mismatches between male and female reproductive traits.
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Affiliation(s)
- Emily G Rose
- Department of Biology, University of Maryland, College Park, Maryland, 20742
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28
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Firman RC, Simmons LW. Sperm competition risk generates phenotypic plasticity in ovum fertilizability. Proc Biol Sci 2013; 280:20132097. [PMID: 24132308 DOI: 10.1098/rspb.2013.2097] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Theory predicts that sperm competition will generate sexual conflict that favours increased ovum defences against polyspermy. A recent study on house mice has shown that ovum resistance to fertilization coevolves in response to increased sperm fertilizing capacity. However, the capacity for the female gamete to adjust its fertilizability as a strategic response to sperm competition risk has never, to our knowledge, been studied. We sourced house mice (Mus domesticus) from natural populations that differ in the level of sperm competition and sperm fertilizing capacity, and manipulated the social experience of females during their sexual development to simulate conditions of either a future 'risk' or 'no risk' of sperm competition. Consistent with coevolutionary predictions, we found lower fertilization rates in ova produced by females from a high sperm competition population compared with ova from a low sperm competition population, indicating that these populations are divergent in the fertilizability of their ova. More importantly, females exposed to a 'risk' of sperm competition produced ova that had greater resistance to fertilization than ova produced by females reared in an environment with 'no risk'. Consequently, we show that variation in sperm competition risk during development generates phenotypic plasticity in ova fertilizability, which allows females to prepare for prevailing conditions during their reproductive life.
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Affiliation(s)
- Renée C Firman
- Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, , Nedlands 6009, Australia
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29
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Medarde N, Martínez-Vargas J, Sánchez-Chardi A, López-Fuster MJ, Ventura J. Effect of Robertsonian translocations on sperm head form in the house mouse. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Nuria Medarde
- Departament de Biologia Animal; de Biologia Vegetal i d'Ecologia; Facultat de Biociències; Universitat Autònoma de Barcelona; E-08193 Cerdanyola del Vallès Spain
| | - Jessica Martínez-Vargas
- Departament de Biologia Animal; de Biologia Vegetal i d'Ecologia; Facultat de Biociències; Universitat Autònoma de Barcelona; E-08193 Cerdanyola del Vallès Spain
| | | | - María José López-Fuster
- Departament de Biologia Animal and Institut de Recerca de la Biodiversitat (IRBio); Facultat de Biologia; Universitat de Barcelona; E-08007 Barcelona Spain
| | - Jacint Ventura
- Departament de Biologia Animal; de Biologia Vegetal i d'Ecologia; Facultat de Biociències; Universitat Autònoma de Barcelona; E-08193 Cerdanyola del Vallès Spain
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30
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Fogarty ND, Lowenberg M, Ojima MN, Knowlton N, Levitan DR. Asymmetric conspecific sperm precedence in relation to spawning times in the Montastraea annularis species complex (Cnidaria: Scleractinia). J Evol Biol 2012; 25:2481-8. [PMID: 23107066 DOI: 10.1111/j.1420-9101.2012.02625.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 07/24/2012] [Accepted: 08/08/2012] [Indexed: 12/13/2022]
Abstract
In broadcast spawners, prezygotic reproductive isolation depends on differences in the spatial and temporal patterns of gamete release and gametic incompatibility. Typically, gametic incompatibility is measured in no-choice crosses, but conspecific sperm precedence (CSP) can prevent hybridization in gametes that are compatible in the absence of sperm competition. Broadcast spawning corals in the Montastraea annularis species complex spawn annually on the same few evenings. Montastraea franksi spawns an average of 110 min before M. annularis, with a minimum gap of approximately 40 min. Gametes are compatible in no-choice heterospecific assays, but it is unknown whether eggs exhibit choice when in competition. Hybridization depends on either M. franksi eggs remaining unfertilized and in proximity to M. annularis when the latter species spawns or M. franksi sperm remaining in sufficient viable concentrations when M. annularis spawns. We found that the eggs of the early spawning M. franksi demonstrate strong CSP, whereas CSP appears to be lacking for M. annularis eggs. This study provides evidence of diverging gamete affinities between these recently separated species and suggests for the first time that selection may favour CSP in earlier spawning species when conspecific sperm is diluted and aged and is otherwise at a numeric and viability disadvantage with heterospecific sperm.
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Affiliation(s)
- N D Fogarty
- Department of Biological Science, Florida State University, Tallahassee, FL, USA.
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31
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Kozlowska JL, Ahmad AR, Jahesh E, Cutter AD. Genetic variation for postzygotic reproductive isolation between Caenorhabditis briggsae and Caenorhabditis sp. 9. Evolution 2011; 66:1180-95. [PMID: 22486697 DOI: 10.1111/j.1558-5646.2011.01514.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The process of speciation is key to the origins of biodiversity, and yet the Caenorhabditis nematode model system has contributed little to this topic. Genetic studies of speciation in the genus are now feasible, owing to crosses between the recently discovered Caenorhabditis sp. 9 and the well-known C. briggsae producing fertile F(1) hybrid females. We dissected patterns of postzygotic reproductive isolation between these species by crossing eight isogenic strains of C. briggsae reciprocally with six strains of C. sp. 9. We determined that overall patterns of reproductive isolation are robust across these genetic backgrounds. However, we also quantified significant heritable variation within each species for interspecific hybrid incompatibilities for total adult progeny, egg-to-adult viability, and the percentage of male progeny. This demonstrates that intraspecific variation for interspecific hybrid incompatibility occurs despite extensive, albeit incomplete, reproductive isolation. Therefore, this emerging general phenomenon of variable reproductive isolation is not restricted to highly interfertile, early-stage incipient species, but also applies to species in the latest stages of the speciation process. Furthermore, we confirm Haldane's rule and demonstrate strongly asymmetric parent-of-origin effects (Darwin's corollary) that consistently manifest more extremely when hermaphroditic C. briggsae serves as maternal parent. These findings highlight Caenorhabditis as an emerging system for understanding the genetics of general patterns of reproductive isolation.
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Affiliation(s)
- Joanna L Kozlowska
- Department of Ecology & Evolutionary Biology, University of Toronto,Toronto, ON, Canada
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32
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Cryptic gametic interactions confer both conspecific and heterospecific advantages in the Chrysochus (Coleoptera: Chrysomelidae) hybrid zone. Genetica 2011; 139:663-76. [DOI: 10.1007/s10709-011-9567-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 03/14/2011] [Indexed: 11/26/2022]
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RAHMÉ J, WIDMER A, KARRENBERG S. Pollen competition as an asymmetric reproductive barrier between two closely relatedSilenespecies. J Evol Biol 2009; 22:1937-43. [DOI: 10.1111/j.1420-9101.2009.01803.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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34
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Martin-Coello J, Dopazo H, Arbiza L, Ausió J, Roldan ERS, Gomendio M. Sexual selection drives weak positive selection in protamine genes and high promoter divergence, enhancing sperm competitiveness. Proc Biol Sci 2009; 276:2427-36. [PMID: 19364735 PMCID: PMC2690471 DOI: 10.1098/rspb.2009.0257] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Phenotypic adaptations may be the result of changes in gene structure or gene regulation, but little is known about the evolution of gene expression. In addition, it is unclear whether the same selective forces may operate at both levels simultaneously. Reproductive proteins evolve rapidly, but the underlying selective forces promoting such rapid changes are still a matter of debate. In particular, the role of sexual selection in driving positive selection among reproductive proteins remains controversial, whereas its potential influence on changes in promoter regions has not been explored. Protamines are responsible for maintaining DNA in a compacted form in chromosomes in sperm and the available evidence suggests that they evolve rapidly. Because protamines condense DNA within the sperm nucleus, they influence sperm head shape. Here, we examine the influence of sperm competition upon protamine 1 and protamine 2 genes and their promoters, by comparing closely related species of Mus that differ in relative testes size, a reliable indicator of levels of sperm competition. We find evidence of positive selection in the protamine 2 gene in the species with the highest inferred levels of sperm competition. In addition, sperm competition levels across all species are strongly associated with high divergence in protamine 2 promoters that, in turn, are associated with sperm swimming speed. We suggest that changes in protamine 2 promoters are likely to enhance sperm swimming speed by making sperm heads more hydrodynamic. Such phenotypic changes are adaptive because sperm swimming speed may be a major determinant of fertilization success under sperm competition. Thus, when species have diverged recently, few changes in gene-coding sequences are found, while high divergence in promoters seems to be associated with the intensity of sexual selection.
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Affiliation(s)
- Juan Martin-Coello
- Reproductive Ecology and Biology Group, Museo Nacional de Ciencias Naturales (CSIC), c/José Gutiérrez Abascal 2, 28006 Madrid, Spain
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