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Cīrulis A, Nordén AK, Churcher AM, Ramm SA, Zadesenets KS, Abbott JK. Sex-limited experimental evolution drives transcriptomic divergence in a hermaphrodite. Genome Biol Evol 2024; 16:evad235. [PMID: 38155579 PMCID: PMC10786194 DOI: 10.1093/gbe/evad235] [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: 02/22/2023] [Revised: 12/12/2023] [Accepted: 12/23/2023] [Indexed: 12/30/2023] Open
Abstract
The evolution of gonochorism from hermaphroditism is linked with the formation of sex chromosomes, as well as the evolution of sex-biased and sex-specific gene expression to allow both sexes to reach their fitness optimum. There is evidence that sexual selection drives the evolution of male-biased gene expression in particular. However, previous research in this area in animals comes from either theoretical models or comparative studies of already old sex chromosomes. We therefore investigated changes in gene expression under 3 different selection regimes for the simultaneous hermaphrodite Macrostomum lignano subjected to sex-limited experimental evolution (i.e. selection for fitness via eggs, sperm, or a control regime allowing both). After 21 and 22 generations of selection for male-specific or female-specific fitness, we characterized changes in whole-organism gene expression. We found that female-selected lines had changed the most in their gene expression. Although annotation for this species is limited, gene ontology term and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggest that metabolic changes (e.g. biosynthesis of amino acids and carbon metabolism) are an important adaptive component. As predicted, we found that the expression of genes previously identified as testis-biased candidates tended to be downregulated in the female-selected lines. We did not find any significant expression differences for previously identified candidates of other sex-specific organs, but this may simply reflect that few transcripts have been characterized in this way. In conclusion, our experiment suggests that changes in testis-biased gene expression are important in the early evolution of sex chromosomes and gonochorism.
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Affiliation(s)
- Aivars Cīrulis
- Department of Biology, Lund University, 223 62 Lund, Sweden
- Laboratory of Microbiology and Pathology, Institute of Food Safety, Animal Health and Environment “BIOR,”Riga LV-1076, Latvia
- Faculty of Biology, University of Latvia, Riga LV-1004, Latvia
| | - Anna K Nordén
- Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Allison M Churcher
- Department of Molecular Biology, National Bioinformatics Infrastructure Sweden, Umeå University, 901 87 Umeå, Sweden
| | - Steven A Ramm
- Department of Evolutionary Biology, Bielefeld University, 33615 Bielefeld, Germany
- UMR 6553 ECOBIO, Université de Rennes, 35042 Rennes, France
| | - Kira S Zadesenets
- Department of Molecular Genetics, Cell Biology and Bionformatics, The Federal Research Center Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russian Federation
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2
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Hakala SM, Fujioka H, Gapp K, De Gasperin O, Genzoni E, Kilner RM, Koene JM, König B, Linksvayer TA, Meurville MP, Negroni MA, Palejowski H, Wigby S, LeBoeuf AC. Socially transferred materials: why and how to study them. Trends Ecol Evol 2022; 38:446-458. [PMID: 36543692 DOI: 10.1016/j.tree.2022.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 11/21/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022]
Abstract
When biological material is transferred from one individual's body to another, as in ejaculate, eggs, and milk, secondary donor-produced molecules are often transferred along with the main cargo, and influence the physiology and fitness of the receiver. Both social and solitary animals exhibit such social transfers at certain life stages. The secondary, bioactive, and transfer-supporting components in socially transferred materials have evolved convergently to the point where they are used in applications across taxa and type of transfer. The composition of these materials is typically highly dynamic and context dependent, and their components drive the physiological and behavioral evolution of many taxa. Our establishment of the concept of socially transferred materials unifies this multidisciplinary topic and will benefit both theory and applications.
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Zadesenets KS, Rubtsov NB. B Chromosomes in Free-Living Flatworms of the Genus Macrostomum (Platyhelminthes, Macrostomorpha). Int J Mol Sci 2021; 22:13617. [PMID: 34948412 PMCID: PMC8708343 DOI: 10.3390/ijms222413617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/14/2021] [Accepted: 12/17/2021] [Indexed: 11/17/2022] Open
Abstract
B chromosomes (Bs) or supernumerary chromosomes are extra chromosomes in the species karyotype that can vary in its copy number. Bs are widespread in eukaryotes. Usually, the Bs of specimens collected from natural populations are the object of the B chromosome studies. We applied another approach analyzing the Bs in animals maintained under the laboratory conditions as lines and cultures. In this study, three species of the Macrostomum genus that underwent a recent whole-genome duplication (WGD) were involved. In laboratory lines of M. lignano and M. janickei, the frequency of Bs was less than 1%, while in the laboratory culture of M. mirumnovem, it was nearer 30%. Their number in specimens of the culture varied from 1 to 14. Mosaicism on Bs was discovered in parts of these animals. We analyzed the distribution of Bs among the worms of the laboratory cultures during long-term cultivation, the transmission rates of Bs in the progeny obtained from crosses of worms with different numbers of Bs, and from self-fertilized isolated worms. The DNA content of the Bs in M. mirumnovem was analyzed with the chromosomal in situ suppression (CISS) hybridization of microdissected DNA probes derived from A chromosomes (As). Bs mainly consisted of repetitive DNA. The cytogenetic analysis also revealed the divergence and high variation in large metacentric chromosomes (LMs) containing numerous regions enriched for repeats. The possible mechanisms of the appearance and evolution of Bs and LMs in species of the Macrostomum genus were also discussed.
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Affiliation(s)
- Kira S. Zadesenets
- The Federal Research Center Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia;
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4
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Wiberg RAW, Brand JN, Schärer L. Faster Rates of Molecular Sequence Evolution in Reproduction-Related Genes and in Species with Hypodermic Sperm Morphologies. Mol Biol Evol 2021; 38:5685-5703. [PMID: 34534329 PMCID: PMC8662610 DOI: 10.1093/molbev/msab276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sexual selection drives the evolution of many striking behaviors and morphologies and should leave signatures of selection at loci underlying these phenotypes. However, although loci thought to be under sexual selection often evolve rapidly, few studies have contrasted rates of molecular sequence evolution at such loci across lineages with different sexual selection contexts. Furthermore, work has focused on separate sexed animals, neglecting alternative sexual systems. We investigate rates of molecular sequence evolution in hermaphroditic flatworms of the genus Macrostomum. Specifically, we compare species that exhibit contrasting sperm morphologies, strongly associated with multiple convergent shifts in the mating strategy, reflecting different sexual selection contexts. Species donating and receiving sperm in every mating have sperm with bristles, likely to prevent sperm removal. Meanwhile, species that hypodermically inject sperm lack bristles, potentially as an adaptation to the environment experienced by hypodermic sperm. Combining functional annotations from the model, Macrostomum lignano, with transcriptomes from 93 congeners, we find genus-wide faster sequence evolution in reproduction-related versus ubiquitously expressed genes, consistent with stronger sexual selection on the former. Additionally, species with hypodermic sperm morphologies had elevated molecular sequence evolution, regardless of a gene's functional annotation. These genome-wide patterns suggest reduced selection efficiency following shifts to hypodermic mating, possibly due to higher selfing rates in these species. Moreover, we find little evidence for convergent amino acid changes across species. Our work not only shows that reproduction-related genes evolve rapidly also in hermaphroditic animals, but also that well-replicated contrasts of different sexual selection contexts can reveal underappreciated genome-wide effects.
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Affiliation(s)
- R Axel W Wiberg
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Jeremias N Brand
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Lukas Schärer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
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5
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Davey PA, Power AM, Santos R, Bertemes P, Ladurner P, Palmowski P, Clarke J, Flammang P, Lengerer B, Hennebert E, Rothbächer U, Pjeta R, Wunderer J, Zurovec M, Aldred N. Omics-based molecular analyses of adhesion by aquatic invertebrates. Biol Rev Camb Philos Soc 2021; 96:1051-1075. [PMID: 33594824 DOI: 10.1111/brv.12691] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/15/2022]
Abstract
Many aquatic invertebrates are associated with surfaces, using adhesives to attach to the substratum for locomotion, prey capture, reproduction, building or defence. Their intriguing and sophisticated biological glues have been the focus of study for decades. In all but a couple of specific taxa, however, the precise mechanisms by which the bioadhesives stick to surfaces underwater and (in many cases) harden have proved to be elusive. Since the bulk components are known to be based on proteins in most organisms, the opportunities provided by advancing 'omics technologies have revolutionised bioadhesion research. Time-consuming isolation and analysis of single molecules has been either replaced or augmented by the generation of massive data sets that describe the organism's translated genes and proteins. While these new approaches have provided resources and opportunities that have enabled physiological insights and taxonomic comparisons that were not previously possible, they do not provide the complete picture and continued multi-disciplinarity is essential. This review covers the various ways in which 'omics have contributed to our understanding of adhesion by aquatic invertebrates, with new data to illustrate key points. The associated challenges are highlighted and priorities are suggested for future research.
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Affiliation(s)
- Peter A Davey
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K
| | - Anne Marie Power
- Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Room 226, Galway, H91 TK33, Ireland
| | - Romana Santos
- Departamento de Biologia Animal, Faculdade de Ciências, Centro de Ciências do Mar e do Ambiente (MARE), Universidade de Lisboa, Lisbon, 1749-016, Portugal
| | - Philip Bertemes
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Peter Ladurner
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Pawel Palmowski
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K
| | - Jessica Clarke
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K
| | - Patrick Flammang
- Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons, Place du Parc 23, Mons, 7000, Belgium
| | - Birgit Lengerer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Elise Hennebert
- Laboratory of Cell Biology, Research Institute for Biosciences, University of Mons, Place du Parc 23, Mons, 7000, Belgium
| | - Ute Rothbächer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Robert Pjeta
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Julia Wunderer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Michal Zurovec
- Biology Centre of the Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice, 370 05, Czech Republic
| | - Nick Aldred
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, U.K
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6
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Ramm SA. Seminal fluid and accessory male investment in sperm competition. Philos Trans R Soc Lond B Biol Sci 2020; 375:20200068. [PMID: 33070740 DOI: 10.1098/rstb.2020.0068] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sperm production and allocation strategies have been a central concern of sperm competition research for the past 50 years. But during the 'sexual cascade' there may be strong selection for alternative routes to maximizing male fitness. Especially with the evolution of internal fertilization, a common and by now well-studied example is the accessory ejaculate investment represented by seminal fluid, the complex mixture of proteins, peptides and other components transferred to females together with sperm. How seminal fluid investment should covary with sperm investment probably depends on the mechanism of seminal fluid action. If seminal fluid components boost male paternity success by directly enhancing sperm function or use, we might often expect a positive correlation between the two forms of male investment, whereas trade-offs seem more likely if seminal fluid acts independently of sperm. This is largely borne out by a broad taxonomic survey to establish the prevailing patterns of seminal fluid production and allocation during animal evolution, in light of which I discuss the gaps that remain in our understanding of this key ejaculate component and its relationship to sperm investment, before outlining promising approaches for examining seminal fluid-mediated sperm competitiveness in the post-genomic era. This article is part of the theme issue 'Fifty years of sperm competition'.
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Affiliation(s)
- Steven A Ramm
- Evolutionary Biology, Bielefeld University, Konsequenz 45, 33615 Bielefeld, Germany
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7
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Singh P, Ballmer DN, Laubscher M, Schärer L. Successful mating and hybridisation in two closely related flatworm species despite significant differences in reproductive morphology and behaviour. Sci Rep 2020; 10:12830. [PMID: 32732887 PMCID: PMC7393371 DOI: 10.1038/s41598-020-69767-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
Reproductive traits are some of the fastest diverging characters and can serve as reproductive barriers. The free-living flatworm Macrostomum lignano, and its congener M. janickei are closely related, but differ substantially in their male intromittent organ (stylet) morphology. Here, we examine whether these morphological differences are accompanied by differences in behavioural traits, and whether these could represent barriers to successful mating and hybridization between the two species. Our data shows that the two species differ in many aspects of their mating behaviour. Despite these differences, the species mate readily with each other in heterospecific pairings. Although both species have similar fecundity in conspecific pairings, the heterospecific pairings revealed clear postmating barriers, as few heterospecific pairings produced F1 hybrids. These hybrids had a stylet morphology that was intermediate between that of the parental species, and they were fertile. Finally, using a mate choice experiment, we show that the nearly two-fold higher mating rate of M. lignano caused it to mate more with conspecifics, leading to assortative mating, while M. janickei ended up mating more with heterospecifics. Thus, while the two species can hybridize, the mating rate differences could possibly lead to higher fitness costs for M. janickei compared to M. lignano.
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Affiliation(s)
- Pragya Singh
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland.
| | - Daniel N Ballmer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland.,Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Max Laubscher
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Lukas Schärer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
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8
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Brand JN, Wiberg RAW, Pjeta R, Bertemes P, Beisel C, Ladurner P, Schärer L. RNA-Seq of three free-living flatworm species suggests rapid evolution of reproduction-related genes. BMC Genomics 2020; 21:462. [PMID: 32631219 PMCID: PMC7336406 DOI: 10.1186/s12864-020-06862-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/22/2020] [Indexed: 01/03/2023] Open
Abstract
Background The genus Macrostomum consists of small free-living flatworms and contains Macrostomum lignano, which has been used in investigations of ageing, stem cell biology, bioadhesion, karyology, and sexual selection in hermaphrodites. Two types of mating behaviour occur within this genus. Some species, including M. lignano, mate via reciprocal copulation, where, in a single mating, both partners insert their male copulatory organ into the female storage organ and simultaneously donate and receive sperm. Other species mate via hypodermic insemination, where worms use a needle-like copulatory organ to inject sperm into the tissue of the partner. These contrasting mating behaviours are associated with striking differences in sperm and copulatory organ morphology. Here we expand the genomic resources within the genus to representatives of both behaviour types and investigate whether genes vary in their rate of evolution depending on their putative function. Results We present de novo assembled transcriptomes of three Macrostomum species, namely M. hystrix, a close relative of M. lignano that mates via hypodermic insemination, M. spirale, a more distantly related species that mates via reciprocal copulation, and finally M. pusillum, which represents a clade that is only distantly related to the other three species and also mates via hypodermic insemination. We infer 23,764 sets of homologous genes and annotate them using experimental evidence from M. lignano. Across the genus, we identify 521 gene families with conserved patterns of differential expression between juvenile vs. adult worms and 185 gene families with a putative expression in the testes that are restricted to the two reciprocally mating species. Further, we show that homologs of putative reproduction-related genes have a higher protein divergence across the four species than genes lacking such annotations and that they are more difficult to identify across the four species, indicating that these genes evolve more rapidly, while genes involved in neoblast function are more conserved. Conclusions This study improves the genus Macrostomum as a model system, by providing resources for the targeted investigation of gene function in a broad range of species. And we, for the first time, show that reproduction-related genes evolve at an accelerated rate in flatworms.
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Affiliation(s)
- Jeremias N Brand
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland.
| | - R Axel W Wiberg
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Robert Pjeta
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Philip Bertemes
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Christian Beisel
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Peter Ladurner
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Lukas Schärer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
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9
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Weber M, Patlar B, Ramm SA. Effects of two seminal fluid transcripts on post-mating behaviour in the simultaneously hermaphroditic flatworm Macrostomum lignano. J Evol Biol 2020; 33:714-726. [PMID: 32064699 DOI: 10.1111/jeb.13606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/29/2020] [Accepted: 02/06/2020] [Indexed: 12/12/2022]
Abstract
The seminal fluid proteins (SFPs) transferred to mating partners along with sperm often play crucial roles in mediating post-mating sexual selection. One way in which sperm donors can maximize their own reproductive success is by modifying the partner's (sperm recipient's) post-copulatory behaviour to prevent or delay re-mating, thereby decreasing the likelihood or intensity of sperm competition. Here, we adopted a quantitative genetic approach combining gene expression and behavioural data to identify candidates that could mediate such a response in the simultaneously hermaphroditic flatworm Macrostomum lignano. We identified two putative SFPs-Mlig-pro46 and Mlig-pro63-linked to both mating frequency and 'suck' frequency, a distinctive behaviour, in which, upon ejaculate receipt, the worm places its pharynx over its female genital opening and apparently attempts to remove the received ejaculate. We, therefore, performed a manipulative experiment using RNA interference-induced knockdown to ask how the loss of Mlig-pro46 and Mlig-pro63 expression, singly and in combination, affects mating frequency, partner suck propensity and sperm competitive ability. None of the knockdown treatments impacted strongly on the mating frequency or sperm competitive ability, but knockdown of Mlig-pro63 resulted in a significantly decreased suck propensity of mating partners. This suggests that Mlig-pro63 may normally act as a cue in the ejaculate to trigger recipient suck behaviour and-given that other proteins in the ejaculate have the opposite effect-could be one component of an ongoing arms race between donors and recipients over the control of ejaculate fate. However, the adaptive significance of Mlig-pro46 and Mlig-pro63 from a donor perspective remains enigmatic.
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Affiliation(s)
- Michael Weber
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - Bahar Patlar
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - Steven A Ramm
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
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10
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Patlar B, Weber M, Temizyürek T, Ramm SA. Seminal Fluid-Mediated Manipulation of Post-mating Behavior in a Simultaneous Hermaphrodite. Curr Biol 2020; 30:143-149.e4. [DOI: 10.1016/j.cub.2019.11.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 09/25/2019] [Accepted: 11/05/2019] [Indexed: 10/25/2022]
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11
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Weber M, Giannakara A, Ramm SA. Seminal fluid-mediated fitness effects in the simultaneously hermaphroditic flatworm Macrostomum lignano. Ecol Evol 2019; 9:13889-13901. [PMID: 31938489 PMCID: PMC6953679 DOI: 10.1002/ece3.5825] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 11/08/2022] Open
Abstract
As a class, seminal fluid proteins are expected to exert strong effects on mating partners due to the selection pressures of sperm competition and sexual conflict. But because of the complexity of this secretion, linking specific proteins to downstream effects on own fitness-via manipulating the reproductive behavior, physiology, and ultimately the sperm utilization of mating partners-is not straightforward. Here, we adopted a systematic gene knockdown approach to screen for seminal fluid-mediated fitness effects in the simultaneously hermaphroditic flatworm Macrostomum lignano. We focused on 18 transcripts in M. lignano seminal fluid, testing how their RNA interference-induced knockdown impacted on three aspects of donor (male) reproductive success: (a) fertility (offspring production of the partner); (b) defensive sperm competitive ability, P 1; and (c) offensive sperm competitive ability, P 2. In general, the knockdown of most individual transcripts appeared to have only a minor impact on male reproductive success, though we found evidence that the knockdown of up to five different transcripts impacted on fertility; the knockdown of two other transcripts resulted in reduced P 2; and knockdown of a further transcript actually increased P 2. We thus identify a number of candidate seminal fluid transcripts that appear to modulate offspring production and sperm competitiveness in M. lignano. That only a minority of transcripts exhibit such a pattern likely reflects both the difficulty of accurately estimating sperm competitiveness and the functional redundancy of seminal fluid.
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Affiliation(s)
- Michael Weber
- Department of Evolutionary BiologyBielefeld UniversityBielefeldGermany
| | - Athina Giannakara
- Department of Evolutionary BiologyBielefeld UniversityBielefeldGermany
| | - Steven A. Ramm
- Department of Evolutionary BiologyBielefeld UniversityBielefeldGermany
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12
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Patlar B, Ramm SA. Genotype‐by‐environment interactions for seminal fluid expression and sperm competitive ability. J Evol Biol 2019; 33:225-236. [DOI: 10.1111/jeb.13568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/25/2019] [Accepted: 11/06/2019] [Indexed: 12/01/2022]
Affiliation(s)
- Bahar Patlar
- Evolutionary Biology Bielefeld University Bielefeld Germany
| | - Steven A. Ramm
- Evolutionary Biology Bielefeld University Bielefeld Germany
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13
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Ramm SA, Lengerer B, Arbore R, Pjeta R, Wunderer J, Giannakara A, Berezikov E, Ladurner P, Schärer L. Sex allocation plasticity on a transcriptome scale: Socially sensitive gene expression in a simultaneous hermaphrodite. Mol Ecol 2019; 28:2321-2341. [PMID: 30891857 DOI: 10.1111/mec.15077] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/04/2019] [Accepted: 03/11/2019] [Indexed: 12/11/2022]
Abstract
Phenotypic plasticity can enable organisms to produce optimal phenotypes in multiple environments. A crucial life history trait that is often highly plastic is sex allocation, which in simultaneous hermaphrodites describes the relative investment into the male versus female sex functions. Theory predicts-and morphological evidence supports-that greater investment into the male function is favoured with increasing group size, due to the increasing importance of sperm competition for male reproductive success. Here, we performed a genome-wide gene expression assay to test for such sex allocation plasticity in a model simultaneous hermaphrodite, the free-living flatworm Macrostomum lignano. Based on RNA-Seq data from 16 biological replicates spanning four different group size treatments, we demonstrate that at least 10% of the >75,000 investigated transcripts in M. lignano are differentially expressed according to the social environment, rising to >30% of putative gonad-specific transcripts (spermatogenesis and oogenesis candidates) and tail-specific transcripts (seminal fluid candidates). This transcriptional response closely corresponds to the expected shift away from female and towards male reproductive investment with increasing sperm competition level. Using whole-mount in situ hybridization, we then confirm that many plastic transcripts exhibit the expected organ-specific expression, and RNA interference of selected testis- and ovary-specific candidates establishes that these indeed function in gametogenesis pathways. We conclude that a large proportion of sex-specific transcripts in M. lignano are differentially expressed according to the prevailing ecological conditions and that these are functionally relevant to key reproductive phenotypes. Our study thus begins to bridge organismal and molecular perspectives on sex allocation plasticity.
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Affiliation(s)
- Steven A Ramm
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany.,Evolutionary Biology, Zoological Institute, University of Basel, Basel, Switzerland
| | - Birgit Lengerer
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | - Roberto Arbore
- Evolutionary Biology, Zoological Institute, University of Basel, Basel, Switzerland
| | - Robert Pjeta
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | - Julia Wunderer
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | | | - Eugene Berezikov
- ERIBA, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter Ladurner
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | - Lukas Schärer
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany
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14
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Patlar B, Weber M, Ramm SA. Genetic and environmental variation in transcriptional expression of seminal fluid proteins. Heredity (Edinb) 2019; 122:595-611. [PMID: 30356222 PMCID: PMC6461930 DOI: 10.1038/s41437-018-0160-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 08/29/2018] [Accepted: 09/18/2018] [Indexed: 12/31/2022] Open
Abstract
Seminal fluid proteins (SFPs) are crucial mediators of sexual selection and sexual conflict. Recent studies have chiefly focused on environmentally induced plasticity as one source of variation in SFP expression, particularly in response to differing sperm competition levels. However, understanding the evolution of a trait in heterogenous environments requires estimates of both environmental and genetic sources of variation, as well as their interaction. Therefore, we investigated how environment (specifically mating group size, a good predictor of sperm competition intensity), genotype and genotype-by-environment interactions affect seminal fluid expression. To do so, we reared 12 inbred lines of a simultaneously hermaphroditic flatworm Macrostomum lignano in groups of either two or eight worms and measured the expression levels of 58 putative SFP transcripts. We then examined the source of variation in the expression of each transcript individually and for multivariate axes extracted from a principal component analysis. We found that mating group size did not affect expression levels according to the single transcript analyses, nor did it affect the first principal component (presumably representing overall investment in seminal fluid production). However, mating group size did affect the relative expression of different transcripts captured by the second principal component (presumably reflecting variation in seminal fluid composition). Most transcripts were genetically variable in their expression level and several exhibited genotype-by-environment interactions; relative composition also showed high genetic variation. Collectively, our results reveal the tightly integrated nature of the seminal fluid transcriptome and provide new insights into the quantitative genetic basis of seminal fluid investment and composition.
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Affiliation(s)
- Bahar Patlar
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany.
| | - Michael Weber
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - Steven A Ramm
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany
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Wunderer J, Lengerer B, Pjeta R, Bertemes P, Kremser L, Lindner H, Ederth T, Hess MW, Stock D, Salvenmoser W, Ladurner P. A mechanism for temporary bioadhesion. Proc Natl Acad Sci U S A 2019; 116:4297-4306. [PMID: 30782790 PMCID: PMC6410801 DOI: 10.1073/pnas.1814230116] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The flatworm Macrostomum lignano features a duo-gland adhesive system that allows it to repeatedly attach to and release from substrates in seawater within a minute. However, little is known about the molecules involved in this temporary adhesion. In this study, we show that the attachment of M. lignano relies on the secretion of two large adhesive proteins, M. lignano adhesion protein 1 (Mlig-ap1) and Mlig-ap2. We revealed that both proteins are expressed in the adhesive gland cells and that their distribution within the adhesive footprints was spatially restricted. RNA interference knockdown experiments demonstrated the essential function of these two proteins in flatworm adhesion. Negatively charged modified sugars in the surrounding water inhibited flatworm attachment, while positively charged molecules impeded detachment. In addition, we found that M. lignano could not adhere to strongly hydrated surfaces. We propose an attachment-release model where Mlig-ap2 attaches to the substrate and Mlig-ap1 exhibits a cohesive function. A small negatively charged molecule is secreted that interferes with Mlig-ap1, inducing detachment. These findings are of relevance for fundamental adhesion science and efforts to mitigate biofouling. Further, this model of flatworm temporary adhesion may serve as the starting point for the development of synthetic reversible adhesion systems for medicinal and industrial applications.
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Affiliation(s)
- Julia Wunderer
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Birgit Lengerer
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
- Biology of Marine Organisms and Biomimetics, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
| | - Robert Pjeta
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Philip Bertemes
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Leopold Kremser
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Thomas Ederth
- Division of Molecular Physics, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
| | - Michael W Hess
- Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - David Stock
- Institute for Material Technology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Willi Salvenmoser
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Peter Ladurner
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria;
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
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