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Lafond J, Angers B. Maternal ploidy shapes reproductive pathways in the triploid hybrid Chrosomus eos × eos-neogaeus. Mol Ecol 2024; 33:e17264. [PMID: 38205506 DOI: 10.1111/mec.17264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/12/2023] [Accepted: 01/04/2024] [Indexed: 01/12/2024]
Abstract
Elements transferred from a mother to her eggs may strongly influence the phenotype of her offspring. Such maternal effects depend on the genotype of the mother, and while multiple ploidy levels occur naturally in some vertebrate species, studies evaluating the impact of maternal ploidy on offspring are scarce. This paper aimed to test whether maternal ploidy is responsible for the two reproductive phenotypes observed in the triploid fish Chrosomus eos × eos-neogaeus. Indeed, these hybrids have two different maternal origins (diploid or triploid) and display two reproductive phenotypes, ameiotic and meiotic hybridogenesis, resulting in diploid and haploid eggs, respectively. To this end, we first conducted a genomic survey to identify epigenetic variations in triploid larvae reared under common garden conditions, concordantly with their maternal origin. The results revealed that the polymorphic epigenetic loci of the larvae clustered into two highly distinct groups consistently with the ploidy of their mother. Diagnostic epigenetic loci were then tested in triploid adult females whose reproductive pathways were already known, to infer their own maternal origin. Altogether, the results suggest that triploid larvae from diploid and triploid mothers will develop the ameiotic and meiotic hybridogenesis pathway, respectively. This confirms that the development of a given reproductive pathway in triploid females results from the ploidy of their mother. Overall, this study supports a strong maternal effect, introducing maternal ploidy and reproductive pathways as additional cause and effect of maternal effects, respectively.
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Affiliation(s)
- Joëlle Lafond
- Department of Biological Sciences, Université de Montréal, Montreal, Quebec, Canada
| | - Bernard Angers
- Department of Biological Sciences, Université de Montréal, Montreal, Quebec, Canada
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2
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Fyon F, Berbel-Filho WM, Schlupp I, Wild G, Úbeda F. Why do hybrids turn down sex? Evolution 2023; 77:2186-2199. [PMID: 37459230 DOI: 10.1093/evolut/qpad129] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 05/19/2023] [Accepted: 07/05/2023] [Indexed: 10/05/2023]
Abstract
Asexual reproduction is ancestral in prokaryotes; the switch to sexuality in eukaryotes is one of the major transitions in the history of life. The study of the maintenance of sex in eukaryotes has raised considerable interest for decades and is still one of evolutionary biology's most prominent question. The observation that many asexual species are of hybrid origin has led some to propose that asexuality in hybrids results from sexual processes being disturbed because of incompatibilities between the two parental species' genomes. However, in some cases, failure to produce asexual F1s in the lab may indicate that this mechanism is not the only road to asexuality in hybrid species. Here, we present a mathematical model and propose an alternative, adaptive route for the evolution of asexuality from previously sexual hybrids. Under some reproductive alterations, we show that asexuality can evolve to rescue hybrids' reproduction. Importantly, we highlight that when incompatibilities only affect the fusion of sperm and egg's genomes, the two traits that characterize asexuality, namely unreduced meiosis and the initiation of embryogenesis without the incorporation of the sperm's pronucleus, can evolve separately, greatly facilitating the overall evolutionary route. Taken together, our results provide an alternative, potentially complementary explanation for the link between asexuality and hybridization.
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Affiliation(s)
- Frédéric Fyon
- Department of Biology, Royal Holloway University of London, Egham, United Kingdom
| | | | - Ingo Schlupp
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Geoff Wild
- Department of Applied Mathematics, University of Western Ontario, London, ON, Canada
| | - Francisco Úbeda
- Department of Biology, Royal Holloway University of London, Egham, United Kingdom
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3
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Bare EA, Bogart JP, Wilson C, Murray DL, Hossie TJ. Diversity and composition of mixed-ploidy unisexual salamander assemblages reflect the key influence of host species. Oecologia 2023; 202:807-818. [PMID: 37615743 DOI: 10.1007/s00442-023-05440-8] [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: 03/17/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023]
Abstract
Understanding processes that govern and sustain biological diversity is a central goal of community ecology. Unisexual complexes, where reproduction depends on sperm from males of one or more bisexual host species, are rare and the processes driving their diversity and structure remain poorly understood. Unisexual Ambystoma salamanders produce distinct biotypes ('genomotypes') depending on which bisexual species they 'steal' sperm from. This reproductive mode should generate distinct assemblages depending on the locally available bisexual host species. Yet, how availability and relative abundance of multiple bisexual hosts influences composition and diversity of natural unisexual assemblages at local or regional scales remains unknown. We hypothesize that host identity most directly drives local assemblage composition, with host variation associated with increased beta and gamma diversity within unisexuals. We collected genetic samples from Ambystoma salamanders across Pelee Island, Ontario, Canada (2015-2022). Two host species were identified (A. texanum and A. laterale) with nine sites having a single host and one site having both. Unisexual assemblages were grouped into four clusters by similarity, with host identity being a key determinant. Gamma diversity increased as a result of distinct host-specific assemblages forming at different sites on the island (i.e., high beta diversity). Assemblage composition, but not diversity, was correlated with relative host abundance, which may reflect matching niche requirements between host and unisexual forms they produce. Our results demonstrate that diversity and structure of unisexual assemblages are clearly shaped by their host(s) and such systems may serve as models for studying how biotic interactions shape ecological communities.
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Affiliation(s)
- Evan A Bare
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, K9L 0G2, Canada.
| | - Jim P Bogart
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Chris Wilson
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, K9L 0G2, Canada
- Aquatic Research and Monitoring Section, Ontario Ministry of Natural Resources and Forestry, Peterborough, ON, Canada
| | - Dennis L Murray
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, K9L 0G2, Canada
- Biology Department, Trent University, Peterborough, ON, K9L 1Z8, Canada
| | - Thomas J Hossie
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, K9L 0G2, Canada
- Biology Department, Trent University, Peterborough, ON, K9L 1Z8, Canada
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4
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Przybył A, Juchno D, Przybylski M, Leska A, Nowosad J, Kucharczyk D, Boroń A. Sex steroids in diploid and triploid gibel carp (Carassius gibelio) of both sexes in different phases of the reproductive cycle. Anim Reprod Sci 2022; 244:107053. [PMID: 35987092 DOI: 10.1016/j.anireprosci.2022.107053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 11/25/2022]
Abstract
The changes in concentrations of 17ß-estradiol (E2), testosterone (T), 11-ketotestosterone (11-KT) in the gonads and plasma of diploid and triploid gibel carp (Carassius gibelio) from the Siemianowka Reservoir, the Vistula River drainage were quantified and compared using an enzyme immunoassay. The phase of gonad maturity was based on histological analysis and the gonadosomatic index. All fish had properly developed gonads in the pre-spawning, spawning and late spawning phases of the reproductive cycle in the fish collected in April, June and October, respectively. Diploid and triploid females and males did not differ in mean GSI in all reproductive phases. In October, ovaries of most females contained vitellogenic oocytes, testes had large numbers of spermatozoa. The hormone concentrations in both tissues depended mainly on the reproductive phase, but not on ploidy. The patterns of changes in E2 concentrations was similar in females and males. In the pre-spawning phase, diploid and triploid females showed differences in the concentrations of 11-KT in gonads and plasma, and T in plasma. Diploid males differed in pattern of T concentrations in gonads and plasma, while all males showed a similar pattern of 11-KT plasma concentrations. Spermatozoa observed in triploid males suggest that they participate in reproduction. Gibel carps, regardless of ploidy, had an extended period of reproduction, which makes this invasive species a potentially greater threat to native ichthyofauna. The sex androgen concentrations that differed between 2 n and 3 n females could be physiological factors potentially contributing to the coexistence of gynogenetic C. gibelio females and sexual diploids.
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Affiliation(s)
- Anna Przybył
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 5 Oczapowskiego Str., 10-718 Olsztyn, Poland
| | - Dorota Juchno
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 5 Oczapowskiego Str., 10-718 Olsztyn, Poland
| | - Mirosław Przybylski
- Department of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha Str., 90-237 Lodz, Poland
| | - Anna Leska
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 5 Oczapowskiego Str., 10-718 Olsztyn, Poland
| | - Joanna Nowosad
- Department of Veterinary Prevention and Feed Hygiene, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, 13 Oczapowskiego Str., 10-718 Olsztyn, Poland; Department of Research and Development, Chemprof, Gutkowo 54B, 11-041 Olsztyn, Poland
| | - Dariusz Kucharczyk
- Department of Ichthyology and Aquaculture, Faculty of Animal Bioengineering, University of Warmia and Mazury in Olsztyn, 5 Oczapowskiego Str., 10-718 Olsztyn, Poland; Department of Research and Development, Chemprof, Gutkowo 54B, 11-041 Olsztyn, Poland
| | - Alicja Boroń
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 5 Oczapowskiego Str., 10-718 Olsztyn, Poland.
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5
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Fuad MMH, Vetešník L, Šimková A. Is gynogenetic reproduction in gibel carp (Carassius gibelio) a major trait responsible for invasiveness? JOURNAL OF VERTEBRATE BIOLOGY 2021. [DOI: 10.25225/jvb.21049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Md Mehedi Hasan Fuad
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic; e-mail: ,
| | - Lukáš Vetešník
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic; e-mail: ,
| | - Andrea Šimková
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic; e-mail: ,
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Dedukh D, Marta A, Janko K. Challenges and Costs of Asexuality: Variation in Premeiotic Genome Duplication in Gynogenetic Hybrids from Cobitis taenia Complex. Int J Mol Sci 2021; 22:ijms222212117. [PMID: 34830012 PMCID: PMC8622741 DOI: 10.3390/ijms222212117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/25/2021] [Accepted: 11/04/2021] [Indexed: 02/07/2023] Open
Abstract
The transition from sexual reproduction to asexuality is often triggered by hybridization. The gametogenesis of many hybrid asexuals involves premeiotic genome endoreplication leading to bypass hybrid sterility and forming clonal gametes. However, it is still not clear when endoreplication occurs, how many gonial cells it affects and whether its rate differs among clonal lineages. Here, we investigated meiotic and premeiotic cells of diploid and triploid hybrids of spined loaches (Cypriniformes: Cobitis) that reproduce by gynogenesis. We found that in naturally and experimentally produced F1 hybrids asexuality is achieved by genome endoreplication, which occurs in gonocytes just before entering meiosis or, rarely, one or a few divisions before meiosis. However, genome endoreplication was observed only in a minor fraction of the hybrid's gonocytes, while the vast majority of gonocytes were unable to duplicate their genomes and consequently could not proceed beyond pachytene due to defects in bivalent formation. We also noted that the rate of endoreplication was significantly higher among gonocytes of hybrids from natural clones than of experimentally produced F1 hybrids. Thus, asexuality and hybrid sterility are intimately related phenomena and the transition from sexual reproduction to asexuality must overcome significant problems with genome incompatibilities with a possible impact on reproductive potential.
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Affiliation(s)
- Dmitrij Dedukh
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics of the CAS, Rumburská 89, 277 21 Liběchov, Czech Republic;
- Correspondence: (D.D.); (K.J.)
| | - Anatolie Marta
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics of the CAS, Rumburská 89, 277 21 Liběchov, Czech Republic;
- Department of Zoology, Faculty of Science, Charles University in Prague, 128 00 Prague, Czech Republic
- Institute of Zoology, MD-2028, Academiei 1, 2001 Chisinau, Moldova
| | - Karel Janko
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics of the CAS, Rumburská 89, 277 21 Liběchov, Czech Republic;
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
- Correspondence: (D.D.); (K.J.)
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Dalziel AC, Tirbhowan S, Drapeau HF, Power C, Jonah LS, Gbotsyo YA, Dion‐Côté A. Using asexual vertebrates to study genome evolution and animal physiology: Banded ( Fundulus diaphanus) x Common Killifish ( F. heteroclitus) hybrid lineages as a model system. Evol Appl 2020; 13:1214-1239. [PMID: 32684956 PMCID: PMC7359844 DOI: 10.1111/eva.12975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/12/2020] [Accepted: 03/16/2020] [Indexed: 12/27/2022] Open
Abstract
Wild, asexual, vertebrate hybrids have many characteristics that make them good model systems for studying how genomes evolve and epigenetic modifications influence animal physiology. In particular, the formation of asexual hybrid lineages is a form of reproductive incompatibility, but we know little about the genetic and genomic mechanisms by which this mode of reproductive isolation proceeds in animals. Asexual lineages also provide researchers with the ability to produce genetically identical individuals, enabling the study of autonomous epigenetic modifications without the confounds of genetic variation. Here, we briefly review the cellular and molecular mechanisms leading to asexual reproduction in vertebrates and the known genetic and epigenetic consequences of the loss of sex. We then specifically discuss what is known about asexual lineages of Fundulus diaphanus x F. heteroclitus to highlight gaps in our knowledge of the biology of these clones. Our preliminary studies of F. diaphanus and F. heteroclitus karyotypes from Porter's Lake (Nova Scotia, Canada) agree with data from other populations, suggesting a conserved interspecific chromosomal arrangement. In addition, genetic analyses suggest that: (a) the same major clonal lineage (Clone A) of F. diaphanus x F. heteroclitus has remained dominant over the past decade, (b) some minor clones have also persisted, (c) new clones may have recently formed, and iv) wild clones still mainly descend from F. diaphanus ♀ x F. heteroclitus ♂ crosses (96% in 2017-2018). These data suggest that clone formation may be a relatively rare, but continuous process, and there are persistent environmental or genetic factors causing a bias in cross direction. We end by describing our current research on the genomic causes and consequences of a transition to asexuality and the potential physiological consequences of epigenetic variation.
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Affiliation(s)
| | - Svetlana Tirbhowan
- Department of BiologySaint Mary's UniversityHalifaxNSCanada
- Département de biologieUniversité de MonctonMonctonNBCanada
| | | | - Claude Power
- Département de biologieUniversité de MonctonMonctonNBCanada
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8
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Lafond J, Hénault P, Leung C, Angers B. Unexpected Oogenic Pathways for the Triploid Fish Chrosomus eos-neogaeus. J Hered 2020; 110:370-377. [PMID: 30597080 DOI: 10.1093/jhered/esy072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/30/2018] [Indexed: 11/14/2022] Open
Abstract
Triploid vertebrates from unisexual complexes often perpetuate themselves asexually. In the fish Chrosomus eos×eos-neogaeus, triploids are continuously produced by diploid hybrids. However, they are not expected to perpetuate since C. eos are their only known progeny. This study aims to investigate the oogenesis of these triploid hybrids through experimental crosses. A total of 337 larvae from 12 female triploids and 3 2n/3n mosaics fertilized with C. eos sperm were genetically characterized. The detection of C. eos as progeny of triploid hybrids confirmed the occurrence of a pathway similar to meiotic hybridogenesis but only for half of the tripoids. The presence of tetraploid offspring for all these females revealed the formation of unreduced triploid eggs as a probable failure of meiotic hybridogenesis. The remaining female triploids and all mosaics produced diploid and triploid hybrids. Triploids excluded the haplome from paternal leakage and produced eggs with the diploid hybrid genome through an ameiotic hybridogenesis. Both types of hybridogenesis occurred in a mutually exclusive manner. This leads us to consider 2 hypothetical scenarios: First, any female triploids can perform either type of hybridogenesis, allowing the long-term persistence of triploid hybrids by a fraction of the population. Alternatively, ameiotic hybridogenesis occurs in triploids of the first generation (from diploid mothers), while meiotic hybridogenesis occurs in triploids of the second generation (from triploid mothers); triploid hybrids then are not perpetuating lineages. The population dynamics of the C. eos-neogaeus complex appears a step more complicated than previously expected.
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Affiliation(s)
- Joëlle Lafond
- Department of Biological Sciences, Université de Montréal, Montreal, Quebec, Canada
| | - Philippe Hénault
- Department of Biological Sciences, Université de Montréal, Montreal, Quebec, Canada
| | - Christelle Leung
- Department of Biological Sciences, Université de Montréal, Montreal, Quebec, Canada
| | - Bernard Angers
- Department of Biological Sciences, Université de Montréal, Montreal, Quebec, Canada
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Monette K, Leung C, Lafond J, Wittische J, Angers B. Inferring responses to climate warming from latitudinal pattern of clonal hybridization. Ecol Evol 2020; 10:307-319. [PMID: 31988730 PMCID: PMC6972808 DOI: 10.1002/ece3.5896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/03/2019] [Accepted: 11/18/2019] [Indexed: 12/02/2022] Open
Abstract
Climate warming may affect reproductive isolation between sympatric sister species by modifying reproductive phenology or mate choice. This is expected to result in a latitudinal progression of hybridization in response to the shifting of environmental conditions. The fish species northern redbelly dace (Chrosomus eos) and finescale dace (C. neogaeus) display a wide sympatric distribution in North America. The asexual reproduction of their hybrids allows determining where and when hybridization occurred. The aim of this study was twofold: first, to assess whether temperature affected reproductive isolation, and second, whether the effects of climate warming resulted in a latitudinal progression of hybridization. We performed a 500 km latitudinal survey (51 sites) in southeastern Quebec (Canada) and determined the distribution of clonal hybrid lineages. Results revealed a total of 78 hybrid lineages, including 70 which originated locally. We detected a significant difference between the southern and northern range of the survey in terms of the proportion of sites harboring local hybrids (20/23 vs. 8/28 sites, respectively) and hybrid diversity (57 vs. 13 lineages, respectively). This confirmed that there was more frequent interspecific mating in the warmest sites. In the southern range, diversity of lineages and simulations suggest that hybridization first took place (>7,000 years) in sites characterized by a longer growing season, followed by northerly adjacent sites (ca. 3,500-5,000 years). Moreover, evidence of hybridization occurring in present-day time was detected. This suggests that the current warming episode is going beyond the limits of the previous warmest period of the Holocene.
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Affiliation(s)
- Katherine Monette
- Department of Biological SciencesUniversité de MontréalMontrealQCCanada
| | - Christelle Leung
- Department of Biological SciencesUniversité de MontréalMontrealQCCanada
| | - Joelle Lafond
- Department of Biological SciencesUniversité de MontréalMontrealQCCanada
| | - Julian Wittische
- Department of Biological SciencesUniversité de MontréalMontrealQCCanada
| | - Bernard Angers
- Department of Biological SciencesUniversité de MontréalMontrealQCCanada
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10
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Leung C, Breton S, Angers B. A trait-based ecology to assess the acclimation of a sperm-dependent clonal fish compared to its sexual host. PeerJ 2018; 6:e5896. [PMID: 30405974 PMCID: PMC6216994 DOI: 10.7717/peerj.5896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/09/2018] [Indexed: 11/20/2022] Open
Abstract
Background Survival in temporally or spatially changing environments is a prerequisite for the perpetuation of a given species. In addition to genetic variation, the role of epigenetic processes is crucial in the persistence of organisms. For instance, mechanisms such as developmental flexibility enable the adjustment of the phenotype of a given individual to changing conditions throughout its development. However, the extent of factors other than genetic variability, like epigenetic processes, in the production of alternative phenotype and the consequences in realized ecological niches is still unclear. Methods In this study, we compared the extent of realized niches between asexual and sexual individuals from different environments. We used a trait-based ecology approach exploiting trophic and locomotive structures to infer the environment that each biotype actually used. More specifically, we compared the morphology of the all-female clonal and sperm-dependent fish Chrosomus eos-neogaeus to that of their sexual host species C. eos in common garden and natural conditions. Results Transfer from natural to controlled conditions resulted in a similar shift in measured morphology for clonal and sexual individuals suggesting comparable level of flexibility in both kinds of organisms. However, clonal, but not sexual, individuals displayed a consistent phenotype when reared in uniform conditions indicating that in absence of genetic variation, one phenotype corresponds to one niche. This contrasted with results from natural conditions where clones were morphologically as variable as sexual individuals within a sampled site. In addition, similar phenotypic changes for both clonal and sexual individuals were observed among the majority of sampled sites, indicating that they responded similarly to the same environments. Discussion Our results indicated that clones can efficiently use different niches and may evolve in a range of environmental conditions comparable to that of a sexual species, thus underlying the importance of factors other than genetic variability, like epigenetic processes, for coping with environmental heterogeneity.
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Affiliation(s)
- Christelle Leung
- Department of Biological Sciences, Université de Montréal, Montréal, QC, Canada
| | - Sophie Breton
- Department of Biological Sciences, Université de Montréal, Montréal, QC, Canada
| | - Bernard Angers
- Department of Biological Sciences, Université de Montréal, Montréal, QC, Canada
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11
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Angers B, Leung C, Vétil R, Deremiens L, Vergilino R. The effects of allospecific mitochondrial genome on the fitness of northern redbelly dace ( Chrosomus eos). Ecol Evol 2018; 8:3311-3321. [PMID: 29607026 PMCID: PMC5869299 DOI: 10.1002/ece3.3922] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 01/17/2018] [Accepted: 01/23/2018] [Indexed: 11/07/2022] Open
Abstract
Instantaneous mitochondrial introgression events allow the disentangling of the effects of hybridization from those of allospecific mtDNA. Such process frequently occurred in the fish Chrosomus eos, resulting in cybrid individuals composed of a C. eos nuclear genome but with a C. neogaeus mtDNA. This provides a valuable model to address the fundamental question: How well do introgressed individuals perform in their native environment? We infer where de novo production of cybrids occurred to discriminate native environments from those colonized by cybrids in 25 sites from two regions (West-Qc and East-Qc) in Quebec (Canada). We then compared the relative abundance of wild types and cybrids as a measure integrating both fitness and de novo production of cybrids. According to mtDNA variation, 12 introgression events are required to explain the diversity of cybrids. Five cybrid lineages could not be associated with in situ introgression events. This includes one haplotype carried by 93% of the cybrids expected to have colonized West-Qc. These cybrids also displayed a nearly complete allopatric distribution with wild types. We still inferred de novo production of cybrids at seven sites, that accounted for 70% of the cybrids in East-Qc. Wild-type and cybrid individuals coexist in all East-Qc sites while cybrids were less abundant. Allopatry of cybrids restricted to the postglacial expansion suggests the existence of higher fitness for cybrids in specific conditions, allowing for the colonization of different environments and expanding the species' range. However, allospecific mtDNA does not provide a higher fitness to cybrids in their native environment compared to wild types, making the success of an introgressed lineage uncertain.
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Affiliation(s)
- Bernard Angers
- Department of Biological Sciences Université de Montréal Montreal QC Canada
| | - Christelle Leung
- Department of Biological Sciences Université de Montréal Montreal QC Canada
| | - Romain Vétil
- Department of Biological Sciences Université de Montréal Montreal QC Canada
| | - Léo Deremiens
- Department of Biological Sciences Université de Montréal Montreal QC Canada
| | - Roland Vergilino
- Department of Biological Sciences Université de Montréal Montreal QC Canada
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12
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Leung C, Angers B. Imitating the cost of males: A hypothesis for coexistence of all-female sperm-dependent species and their sexual host. Ecol Evol 2017; 8:266-272. [PMID: 29321869 PMCID: PMC5756870 DOI: 10.1002/ece3.3681] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 09/22/2017] [Accepted: 11/08/2017] [Indexed: 11/05/2022] Open
Abstract
All-female sperm-dependent species are particular asexual organisms that must coexist with a closely related sexual host for reproduction. However, demographic advantages of asexual over sexual species that have to produce male individuals could lead both to extinction. The unresolved question of their coexistence still challenges and fascinates evolutionary biologists. As an alternative hypothesis, we propose those asexual organisms are afflicted by a demographic cost analogous to the production of males to prevent exclusion of the host. Previously proposed hypotheses stated that asexual individuals relied on a lower fecundity than sexual females to cope with demographic advantage. In contrast, we propose that both sexual and asexual species display the same number of offspring, but half of asexual individuals imitate the cost of sex by occupying ecological niches but producing no offspring. Simulations of population growth in closed systems under different demographic scenarios revealed that only the presence of nonreproductive individuals in asexual females can result in long-term coexistence. This hypothesis is supported by the fact that half of the females in some sperm-dependent organisms did not reproduce clonally.
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Affiliation(s)
- Christelle Leung
- Department of Biological Sciences Université de Montréal Montreal QC Canada
| | - Bernard Angers
- Department of Biological Sciences Université de Montréal Montreal QC Canada
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