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Milich KM. Male-philopatric nonhuman primates and their potential role in understanding the evolution of human sociality. Evol Anthropol 2024; 33:e22014. [PMID: 38109039 DOI: 10.1002/evan.22014] [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: 08/25/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 12/19/2023]
Abstract
In most primate species, males transfer out of their natal groups, resulting in groups of unrelated males. However, in a few species, including humans, males remain in their groups and form life-long associations with each other. This pattern of male philopatry is linked with cooperative male behaviors, including border patrols and predator defense. Because females in male-philopatric species form weaker kin networks with each other than in female-philopatric species, they are expected to evolve counter-strategies to male sexual coercion that are relatively independent of support from other females. Studies of male-philopatric nonhuman primates can provide insight into the evolutionary basis of prosocial behaviors, cooperation, and group action in humans and offer comparative models for understanding the sociality of other hominin species. This review will discuss patterns of dispersal and philopatry across primates, explore the resulting male and female behaviors, and argue that male-philopatric nonhuman primate species offer insight into the social and sexual dynamics of hominins throughout evolution.
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Affiliation(s)
- Krista M Milich
- Department of Anthropology, Washington University in St. Louis, St. Louis, Missouri, USA
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2
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Hadlow JH, Lymbery RA, Evans JP. Paternal environment effects are driven by female reproductive fluid but not sperm age in an external fertilizer. Biol Lett 2023; 19:20230368. [PMID: 37991195 PMCID: PMC10664279 DOI: 10.1098/rsbl.2023.0368] [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: 08/14/2023] [Accepted: 11/06/2023] [Indexed: 11/23/2023] Open
Abstract
Sperm ageing after ejaculation can generate paternal environment effects that impact offspring fitness. In many species, female reproductive fluids (FRFs), i.e. ancillary fluids released by eggs or within the female reproductive tract, may protect sperm from ageing and can additionally interact with sperm to influence offspring viability. This raises the intriguing prospect that FRFs may alleviate paternal effects associated with sperm ageing. Here, we test this novel hypothesis using the broadcast spawning mussel, Mytilus galloprovincialis. We show that incubating sperm in FRF prior to fertilization increases offspring viability, and that these effects occur independently of sperm age. Our results provide novel evidence that FRFs allow females to selectively bias fertilization toward higher quality sperm within an ejaculate, which in turn yields more viable offspring. We consider this FRF-mediated paternal effect in the context of female physiological control over fertilization and the transgenerational effects of female-regulated haploid selection.
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Affiliation(s)
- Jessica H. Hadlow
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Rowan A. Lymbery
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Jonathan P. Evans
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
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3
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Mahdjoub H, Khelifa R, Roy J, Sbilordo SH, Zeender V, Perdigón Ferreira J, Gourgoulianni N, Lüpold S. Interplay between male quality and male-female compatibility across episodes of sexual selection. SCIENCE ADVANCES 2023; 9:eadf5559. [PMID: 37774022 PMCID: PMC10541500 DOI: 10.1126/sciadv.adf5559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 08/30/2023] [Indexed: 10/01/2023]
Abstract
The processes underlying mate choice profoundly influence the dynamics of sexual selection and the evolution of male sexual traits. Consistent preference for certain phenotypes may erode genetic variation in populations through directional selection, whereas divergent preferences (e.g., genetically compatible mates) provide one mechanism to maintain such variation. However, the relative contributions of these processes across episodes of selection remain unknown. Using Drosophila melanogaster, we followed the fate of male genotypes, previously scored for their overall reproductive value and their compatibility with different female genotypes, across pre- and postmating episodes of selection. When pairs of competitor males differed in their intrinsic quality and their compatibility with the female, both factors influenced outcomes from mating success to paternity but to a varying degree between stages. These results add further dimensions to our understanding of how the interactions between genotypes and forms of selection shape reproductive outcomes and ultimately reproductive trait evolution.
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Affiliation(s)
- Hayat Mahdjoub
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Biology Department, Concordia University, 7141 Sherbrooke St. W., Montreal QC H4B 1R6, Canada
| | - Rassim Khelifa
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Biology Department, Concordia University, 7141 Sherbrooke St. W., Montreal QC H4B 1R6, Canada
| | - Jeannine Roy
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Sonja H. Sbilordo
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Valérian Zeender
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Jhoniel Perdigón Ferreira
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Natalia Gourgoulianni
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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4
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Ray King K, Fuselier L, Sirvisetty H. LGBTQIA+ invisibility in nursing anatomy/physiology textbooks. J Prof Nurs 2021; 37:816-827. [PMID: 34742510 DOI: 10.1016/j.profnurs.2021.06.004] [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: 01/28/2021] [Indexed: 12/12/2022]
Abstract
Members of the LGBTQIA+ experience health disparities that are compounded by providers that lack cultural competence, i.e., the skills, attitudes, and knowledge to offer culturally sensitive care. Educational efforts focus on increasing LGBTQIA+ representation across undergraduate nursing curricula and the recruitment and retention of members of this community into nursing programs. However, the ways that classroom materials represent LGBTQIA+ people can perpetuate social norms rather than accurate scientific understandings, thus limiting students' development of cultural competence while also driving LGBTQIA+ students from nursing. This study performs a content analysis for LGBTQIA+ inclusion in four widely adopted undergraduate nursing anatomy/physiology textbooks. We identify specific social beliefs that exclude LGBTQIA+ people and compare the different ways these manifested in each of the four textbooks. We argue that the way these books represent LGBTQIA+ people violate the fundamental ethical principles of nursing. Based on our findings, we challenge educators to consider the impact that language, images, and other classroom materials have on LGBTQIA+ students and all students' ability to develop cultural competence.
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Affiliation(s)
- Katherine Ray King
- Department of Biology, University of Louisville, Life Sciences Building #139, Louisville, KY 40208, USA.
| | - Linda Fuselier
- Department of Biology, University of Louisville, Life Sciences Building #139, Louisville, KY 40208, USA.
| | - Harshini Sirvisetty
- Department of Biology, University of Louisville, Life Sciences Building #139, Louisville, KY 40208, USA.
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5
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Brun S, Kuo HC, Jeffree CE, Thomson DD, Read N. Courtship Ritual of Male and Female Nuclei during Fertilization in Neurospora crassa. Microbiol Spectr 2021; 9:e0033521. [PMID: 34612669 PMCID: PMC8509652 DOI: 10.1128/spectrum.00335-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/25/2021] [Indexed: 11/20/2022] Open
Abstract
Sexual reproduction is a key process influencing the evolution and adaptation of animals, plants, and many eukaryotic microorganisms, such as fungi. However, the sequential cell biology of fertilization and the associated nuclear dynamics after plasmogamy are poorly understood in filamentous fungi. Using histone-fluorescent parental isolates, we tracked male and female nuclei during fertilization in the model ascomycete Neurospora crassa using live-cell imaging. This study unravels the behavior of trichogyne resident female nuclei and the extraordinary manner in which male nuclei migrate up the trichogyne to the protoperithecium. Our observations raise new fundamental questions about the modus operandi of nucleus movements during sexual reproduction, male and female nuclear identity, guidance of nuclei within the trichogyne and, unexpectedly, the avoidance of "polyspermy" in fungi. The spatiotemporal dynamics of male nuclei within the trichogyne following plasmogamy are also described, where the speed and the deformation of male nuclei are of the most dramatic observed to date in a living organism. IMPORTANCE Using live-cell fluorescence imaging, for the first time we have observed live male and female nuclei during sexual reproduction in the model fungus Neurospora crassa. This study reveals the specific behavior of resident female nuclei within the trichogyne (the female organ) after fertilization and the extraordinary manner in which male nuclei migrate across the trichogyne toward their final destination, the protoperithecium, where karyogamy takes place. Importantly, the speed and deformation of male nuclei were found to be among the most dramatic ever observed in a living organism. Furthermore, we observed that entry of male nuclei into protoperithecia may block the entry of other male nuclei, suggesting that a process analogous to polyspermy avoidance could exist in fungi. Our live-cell imaging approach opens new opportunities for novel research on cell-signaling during sexual reproduction in fungi and, on a broader scale, nuclear dynamics in eukaryotes.
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Affiliation(s)
- Sylvain Brun
- Laboratoire Interdisciplinaire des Energies de Demain, CNRS UMR 8236, Université de Paris, Paris, France
| | - Hsiao-Che Kuo
- Fungal Cell Biology Group, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Chris E. Jeffree
- Fungal Cell Biology Group, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Darren D. Thomson
- Manchester Fungal Infection Group, Division of Infection, Immunity, and Respiratory Medicine, University of Manchester, Manchester, United Kingdom
| | - Nick Read
- Manchester Fungal Infection Group, Division of Infection, Immunity, and Respiratory Medicine, University of Manchester, Manchester, United Kingdom
- Fungal Cell Biology Group, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
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6
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Assersohn K, Brekke P, Hemmings N. Physiological factors influencing female fertility in birds. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202274. [PMID: 34350009 PMCID: PMC8316823 DOI: 10.1098/rsos.202274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 07/12/2021] [Indexed: 05/30/2023]
Abstract
Fertility is fundamental to reproductive success, but not all copulation attempts result in a fertilized embryo. Fertilization failure is especially costly for females, but we still lack a clear understanding of the causes of variation in female fertility across taxa. Birds make a useful model system for fertility research, partly because their large eggs are easily studied outside of the female's body, but also because of the wealth of data available on the reproductive productivity of commercial birds. Here, we review the factors contributing to female infertility in birds, providing evidence that female fertility traits are understudied relative to male fertility traits, and that avian fertility research has been dominated by studies focused on Galliformes and captive (relative to wild) populations. We then discuss the key stages of the female reproductive cycle where fertility may be compromised, and make recommendations for future research. We particularly emphasize that studies must differentiate between infertility and embryo mortality as causes of hatching failure, and that non-breeding individuals should be monitored more routinely where possible. This review lays the groundwork for developing a clearer understanding of the causes of female infertility, with important consequences for multiple fields including reproductive science, conservation and commercial breeding.
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Affiliation(s)
- Katherine Assersohn
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Patricia Brekke
- Institute of Zoology, Zoological Society of London, Regents Park, London NW1 4RY, UK
| | - Nicola Hemmings
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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7
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Keeble S, Firman RC, Sarver BAJ, Clark NL, Simmons LW, Dean MD. Evolutionary, proteomic, and experimental investigations suggest the extracellular matrix of cumulus cells mediates fertilization outcomes. Biol Reprod 2021; 105:1043-1055. [PMID: 34007991 DOI: 10.1093/biolre/ioab082] [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] [Received: 08/27/2020] [Revised: 01/29/2021] [Accepted: 04/21/2021] [Indexed: 12/20/2022] Open
Abstract
Studies of fertilization biology often focus on sperm and egg interactions. However, before gametes interact, mammalian sperm must pass through the cumulus layer; in mice, this consists of several thousand cells tightly glued together with hyaluronic acid and other proteins. To better understand the role of cumulus cells and their surrounding matrix, we perform proteomic experiments on cumulus oophorus complexes (COCs) in house mice (Mus musculus), producing over 24,000 mass spectra to identify 711 proteins. Seven proteins known to stabilize hyaluronic acid and the extracellular matrix were especially abundant (using spectral counts as an indirect proxy for abundance). Through comparative evolutionary analyses, we show that three of these evolve rapidly, a classic signature of genes that influence fertilization rate. Some of the selected sites overlap regions of the protein known to impact function. In a follow-up experiment, we compared COCs from females raised in two different social environments. Female mice raised in the presence of multiple males produced COCs that were smaller and more resistant to sperm-derived hyaluronidase compared to females raised in the presence of a single male, consistent with a previous study that demonstrated such females produced COCs that were more resistant to fertilization. Although cumulus cells are often thought of as enhancers of fertilization, our evolutionary, proteomic, and experimental investigations implicate their extracellular matrix as a potential mediator of fertilization outcomes.
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Affiliation(s)
- Sara Keeble
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California
| | - Renée C Firman
- Centre for Evolutionary Biology, School of Biological Sciences (M092), University of Western Australia, Australia
| | - Brice A J Sarver
- Division of Biological Sciences, University of Montana, Missoula, Montana
| | - Nathan L Clark
- Department of Human Genetics, University of Utah, Salt Lake City, Utah
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences (M092), University of Western Australia, Australia
| | - Matthew D Dean
- Molecular and Computational Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California
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8
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Matsuzaki M, Hirohashi N, Tsudzuki M, Haqani MI, Maeda T, Mizushima S, Sasanami T. Longer and faster sperm exhibit better fertilization success in Japanese quail. Poult Sci 2021; 100:100980. [PMID: 33610899 PMCID: PMC7905478 DOI: 10.1016/j.psj.2021.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/18/2020] [Accepted: 01/01/2021] [Indexed: 11/06/2022] Open
Abstract
In birds, sperm storage tubules (SST) located in the utero-vaginal junction are thought to be a site of sperm selection; however, the exact mechanism of sperm selection is poorly understood. Here, we investigated sperm entry into the SST and subsequent fertilization success under a competitive situation created by artificial insemination of a sperm mixture obtained from 2 males. We employed 2 quail strains, a wild-type and a dominant black (DB) type, as this allows easy assessment of paternity by feather coloration. We found paternity of embryos was biased toward DB males when a sperm mix with similar sperm numbers from the 2 males strains was artificially inseminated into females. Our novel sperm staining method with 2 different fluorescent dyes showed that the DB-biased fertilization was because of the better ability of DB sperm to enter the SST. Moreover, we found that DB sperm had a longer flagellum and midpiece. These characteristics probably allow sperm to swim faster in a high viscosity medium, which may be a similar environment to the lumen of the female reproductive tract. Our results indicated that sperm competition occurs to win a place in the SST and that filling the SST with their own spermatozoa is a critical step to achieve better fertilization success for the male Japanese quail.
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Affiliation(s)
- Mei Matsuzaki
- Program of Food and AgriLife Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Noritaka Hirohashi
- Oki Marine Biological Station, Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University, Oki, Shimane 685-0024, Japan
| | - Masaoki Tsudzuki
- Laboratory of Animal Breeding and Genetics, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Mohammad Ibrahim Haqani
- Laboratory of Animal Breeding and Genetics, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Teruo Maeda
- Laboratory of Animal Reproduction, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Shusei Mizushima
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan
| | - Tomohiro Sasanami
- Department of Applied Life Sciences, Faculty of Agriculture, Shizuoka University, Shizuoka City, Shizuoka 422-8529, Japan; Japanese Avian Bioresource Project Research Center, Hiroshima University, Higashi-Hiroshima City, Hiroshima 739-8528, Japan.
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9
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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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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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11
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Gasparini C, Pilastro A, Evans JP. The role of female reproductive fluid in sperm competition. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200077. [PMID: 33070736 DOI: 10.1098/rstb.2020.0077] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The role of non-gametic components of the ejaculate (seminal fluid) in fertility and sperm competitiveness is now well established. Surprisingly, however, we know far less about female reproductive fluid (FRF) in the context of sexual selection, and insights into male-FRF interactions in the context of sperm competition have only recently emerged. Despite this limited knowledge, evidence from taxonomically diverse species has revealed insights into the effects of FRF on sperm traits that have previously been implicated in studies of sperm competition. Specifically, through the differential effects of FRF on a range of sperm traits, including chemoattraction and alterations in sperm velocity, FRF has been shown to exert positive phenotypic effects on the sperm of males that are preferred as mating partners, or those from the most compatible or genetically diverse males. Despite these tantalizing insights into the putative sexually selected functions of FRF, we largely lack a mechanistic understanding of these processes. Taken together, the evidence presented here highlights the likely ubiquity of FRF-regulated biases in fertilization success across a diverse range of taxa, thus potentially elevating the importance of FRF to other non-gametic components that have so far been studied largely in males. This article is part of the theme issue 'Fifty years of sperm competition'.
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Affiliation(s)
- Clelia Gasparini
- Department of Biology, University of Padova, Padova 35131, Italy
| | - Andrea Pilastro
- Department of Biology, University of Padova, Padova 35131, Italy
| | - Jonathan P Evans
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 6009 WA, Australia
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12
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Abstract
Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.
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Affiliation(s)
- John E Schjenken
- Robinson Research Institute and Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Sarah A Robertson
- Robinson Research Institute and Adelaide Medical School, University of Adelaide, Adelaide, Australia
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