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Besnier F, Skaala Ø, Wennevik V, Ayllon F, Utne KR, Fjeldheim PT, Andersen-Fjeldheim K, Knutar S, Glover KA. Overruled by nature: A plastic response to environmental change disconnects a gene and its trait. Mol Ecol 2024; 33:e16933. [PMID: 36942798 DOI: 10.1111/mec.16933] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/21/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023]
Abstract
In Atlantic salmon, age at maturation is a life history trait governed by a sex-specific trade-off between reproductive success and survival. Following environmental changes across large areas of the Northeast Atlantic, many populations currently display smaller size at age and higher age at maturation. However, whether these changes reflect rapid evolution or plasticity is unknown. Approximately 1500 historical and contemporary salmon from the river Etne in Western Norway, genotyped at 50,000 SNPs, revealed three loci associated with age at maturation. These included vgll3 and six6 which collectively explained 36%-50% of the age at maturation variation in the 1983-1984 period. These two loci also displayed sex-specific epistasis, as the effect of six6 was only detected in males bearing two copies of the late maturation allele for vgll3. Strikingly, despite allelic frequencies at vgll3 remaining unchanged, the combined influence of these genes was nearly absent in all samples from 2013 to 2016, and genome-wide heritability strongly declined between the two time-points. The difference in age at maturation between males and females was upheld in the population despite the loss of effect from the candidate loci, which strongly points towards additional causative mechanisms resolving the sexual conflict. Finally, because admixture with farmed escaped salmon was excluded as the origin of the observed disconnection between gene(s) and maturation age, we conclude that the environmental changes observed in the North Atlantic during the past decades have led to bypassing of the influence of vgll3 and six6 on maturation through growth-driven plasticity.
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Moghadam HK, Fannemel B, Thorland I, Lozano C, Hillestad B. Identification and Genomic Localization of Autosomal sdY Locus in a Population of Atlantic Salmon (Salmo salar). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2023:10.1007/s10126-023-10217-4. [PMID: 37233880 DOI: 10.1007/s10126-023-10217-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/14/2023] [Indexed: 05/27/2023]
Abstract
The determination of sex in salmonid fishes is controlled by genetic mechanisms, with males being the heterogametic sex. The master sex-determining gene, the sexually dimorphic gene on the Y chromosome (sdY), is a conserved gene across various salmonid species. Nevertheless, variations in the genomic location of sdY have been observed both within and between species. Furthermore, different studies have reported discordances in the association between the sdY and the phenotypic gender. While some males seem to lack this locus, there have been reports of females carrying sdY. Although the exact reasons behind this discordance remain under investigation, some recent studies have proposed the existence of an autosomal, non-functional copy of sdY as a potential cause. In this study, we confirmed the presence of this autosomal sdY in the SalmoBreed strain of Atlantic salmon using a genotyping platform through a novel approach that allows for high-throughput screening of a large number of individuals. We further characterized the segregation profile of this locus across families and found the ratio of genetically assigned female-to-male progeny to be in accordance with the expected profile of a single autosomal sdY locus. Additionally, our mapping efforts localized this locus to chromosome 3 and suggested a putative copy on chromosome 6.
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Brown MS, Evans BS, Afonso LOB. Developmental changes in gene expression and gonad morphology during sex differentiation in Atlantic salmon (Salmo salar). Gene 2022; 823:146393. [PMID: 35248662 DOI: 10.1016/j.gene.2022.146393] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 02/21/2022] [Accepted: 02/28/2022] [Indexed: 11/04/2022]
Abstract
The Atlantic salmon (Salmo salar) is a globally important species for its value in fisheries and aquaculture, and as a research model. In order to characterise aspects of sex differentiation at the morphological and mRNA level in this species, the present study examined developmental changes in gonad morphology and gene expression in males and females between 0 and 79 days post hatch (dph). Morphological differentiation of the ovary (indicated by the formation of germ cell cysts) became apparent from 52 dph. By 79 dph, ovarian phenotype was evident in 100% of genotypic females. Testes remained in an undifferentiated-like state throughout the experiment, containing germ cells dispersed singularly within the gonadal region distal to the mesentery. There were no significant sex-related differences in gonad cross-section size, germ cell number or germ cell diameter during the experiment. The expression of genes involved in teleost sex differentiation (anti-müllerian hormone (amh), cytochrome P450, family 19, subfamily A, polypeptide 1a (cyp19a1a), forkhead box L2a (foxl2a), gonadal soma-derived factor (gsdf), r-spondin 1 (rspo1), sexually dimorphic on the Y chromosome (sdY)), retinoic acid-signalling (aldehyde dehydrogenase 1a2 (aldh1a2), cytochrome P450 family 26 a1 (cyp26a1), cytochrome P450 family 26 b1 (cyp26b1), t-box transcription factor 1 (tbx1a)) and neuroestrogen production (cytochrome P450, family 19, subfamily A, polypeptide 1b (cyp19a1b)) was investigated. Significant sex-related differences were observed only for the expression of amh, cyp19a1a, gsdf and sdY. In males, amh, gsdf and sdY were upregulated from 34, 59 and 44 dph respectively. In females, cyp19a1a was upregulated from 66 dph. Independent of sex, foxl2a expression was highest at 0 dph and had reduced ∼ 47-fold by the time of morphological sex differentiation at 52 dph. This study provides new insights into the timing and sequence of some physiological changes associated with sex differentiation in Atlantic salmon. These findings also reveal that some aspects of the mRNA sex differentiation pathways in Atlantic salmon are unique compared to other teleost fishes, including other salmonids.
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Affiliation(s)
- Morgan S Brown
- School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University Warrnambool Campus, Warrnambool, Victoria 3280, Australia.
| | - Brad S Evans
- Tassal Operations, Hobart, Tasmania 7000, Australia.
| | - Luis O B Afonso
- School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University Waurn Ponds Campus, Geelong, Victoria 3220, Australia.
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Palejowski H, Bylemans J, Ammann V, Marques da Cunha L, Nusbaumer D, Castro I, Uppal A, Mobley KB, Knörr S, Wedekind C. Sex-Specific Life History Affected by Stocking in Juvenile Brown Trout. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.869925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Salmonids are a socioeconomically and ecologically important group of fish that are often managed by stocking. Little is known about potential sex-specific effects of stocking, but recent studies found that the sexes differ in their stress tolerances already at late embryonic stage, i.e., before hatchery-born larvae are released into the wild and long before morphological gonad formation. It has also been speculated that sex-specific life histories can affect juvenile growth and mortality, and that a resulting sex-biassed demography can reduce population growth. Here we test whether juvenile brown trout (Salmo trutta) show sex-specific life histories and whether such sex effects differ in hatchery- and wild-born fish. We modified a genetic sexing protocol to reduce false assignment rates and used it to study the timing of sex differentiation in a laboratory setting, and in a large-scale field experiment to study growth and mortality of hatchery- and wild-born fish in different environments. We found no sex-specific mortality in any of the environments we studied. However, females started sex differentiation earlier than males, and while growth rates were similar in the laboratory, they differed significantly in the field depending on location and origin of fish. Overall, hatchery-born males grew larger than hatchery-born females while wild-born fish showed the reverse pattern. Whether males or females grew larger was location-specific. We conclude that juvenile brown trout show sex-specific growth that is affected by stocking and by other environmental factors that remain to be identified.
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Dynamics of sexual development in teleosts with a note on Mugil cephalus. AQUACULTURE AND FISHERIES 2022. [DOI: 10.1016/j.aaf.2022.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Besnier F, Ayllon F, Skaala Ø, Solberg MF, Fjeldheim PT, Anderson K, Knutar S, Glover KA. Introgression of domesticated salmon changes life history and phenology of a wild salmon population. Evol Appl 2022; 15:853-864. [PMID: 35603027 PMCID: PMC9108307 DOI: 10.1111/eva.13375] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 03/03/2022] [Accepted: 03/09/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- F. Besnier
- Institute of Marine Research PO box 1870 Nordnes N‐5817 Norway
| | - F. Ayllon
- Institute of Marine Research PO box 1870 Nordnes N‐5817 Norway
| | - Ø. Skaala
- Institute of Marine Research PO box 1870 Nordnes N‐5817 Norway
| | - M. F. Solberg
- Institute of Marine Research PO box 1870 Nordnes N‐5817 Norway
| | | | - K. Anderson
- Institute of Marine Research PO box 1870 Nordnes N‐5817 Norway
| | - S. Knutar
- Institute of Marine Research PO box 1870 Nordnes N‐5817 Norway
| | - K. A. Glover
- Institute of Marine Research PO box 1870 Nordnes N‐5817 Norway
- Department of Biological Sciences University of Bergen N‐5020 Bergen Norway
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Bertho S, Herpin A, Jouanno E, Yano A, Bobe J, Parrinello H, Journot L, Guyomard R, Muller T, Swanson P, McKinney G, Williamson K, Meek M, Schartl M, Guiguen Y. A nonfunctional copy of the salmonid sex-determining gene ( sdY) is responsible for the “apparent” XY females in Chinook salmon, Oncorhynchus tshawytscha. G3 GENES|GENOMES|GENETICS 2022; 12:6493265. [PMID: 35100376 PMCID: PMC8824802 DOI: 10.1093/g3journal/jkab451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 12/03/2021] [Indexed: 11/14/2022]
Abstract
Abstract
Many salmonids have a male heterogametic (XX/XY) sex determination system, and they are supposed to have a conserved master sex-determining gene (sdY) that interacts at the protein level with Foxl2 leading to the blockage of the synergistic induction of Foxl2 and Nr5a1 of the cyp19a1a promoter. However, this hypothesis of a conserved master sex-determining role of sdY in salmonids is challenged by a few exceptions, one of them being the presence of naturally occurring “apparent” XY Chinook salmon, Oncorhynchus tshawytscha, females. Here, we show that some XY Chinook salmon females have a sdY gene (sdY-N183), with 1 missense mutation leading to a substitution of a conserved isoleucine to an asparagine (I183N). In contrast, Chinook salmon males have both a nonmutated sdY-I183 gene and the missense mutation sdY-N183 gene. The 3-dimensional model of SdY-I183N predicts that the I183N hydrophobic to hydrophilic amino acid change leads to a modification in the SdY β-sandwich structure. Using in vitro cell transfection assays, we found that SdY-I183N, like the wild-type SdY, is preferentially localized in the cytoplasm. However, compared to wild-type SdY, SdY-I183N is more prone to degradation, its nuclear translocation by Foxl2 is reduced, and SdY-I183N is unable to significantly repress the synergistic Foxl2/Nr5a1 induction of the cyp19a1a promoter. Altogether, our results suggest that the sdY-N183 gene of XY Chinook females is nonfunctional and that SdY-I183N is no longer able to promote testicular differentiation by impairing the synthesis of estrogens in the early differentiating gonads of wild Chinook salmon XY females.
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Affiliation(s)
- Sylvain Bertho
- INRAE, LPGP, Rennes 35000, France
- Physiological Chemistry, Biocenter, University of Wuerzburg, Wuerzburg 97074, Germany
| | | | | | | | | | - Hugues Parrinello
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, Montpellier 34094, France
| | - Laurent Journot
- Institut de Génomique Fonctionnelle, IGF, CNRS, INSERM, Univ. Montpellier, Montpellier 34094, France
| | - René Guyomard
- GABI, INRAE, AgroParisTech, Université Paris-Saclay, Paris 75005, France
| | - Thomas Muller
- Julius-von-Sachs-Institute, Department of Molecular Plant Physiology and Biophysics, University of Wuerzburg, Wuerzburg 97082, Germany
| | - Penny Swanson
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA
| | - Garrett McKinney
- Molecular Genetics Laboratory, Washington Department of Fish & Wildlife, Olympia, WA 98501, USA
| | | | - Mariah Meek
- Dept. of Integrative Biology, AgBio Research, and Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - Manfred Schartl
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
- Department of Developmental Biochemistry, Biocenter, University of Wüerzburg, Wuerzburg 97074, Germany
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Duval E, Skaala Ø, Quintela M, Dahle G, Delaval A, Wennevik V, Glover KA, Hansen MM. Long-term monitoring of a brown trout (Salmo trutta) population reveals kin-associated migration patterns and contributions by resident trout to the anadromous run. BMC Ecol Evol 2021; 21:143. [PMID: 34256705 PMCID: PMC8276402 DOI: 10.1186/s12862-021-01876-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/02/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND In species showing partial migration, as is the case for many salmonid fishes, it is important to assess how anthropogenic pressure experienced by migrating individuals affects the total population. We focused on brown trout (Salmo trutta) from the Guddal River in the Norwegian Hardanger Fjord system, which encompasses both resident and anadromous individuals. Aquaculture has led to increased anthropogenic pressure on brown trout during the marine phase in this region. Fish traps in the Guddal River allow for sampling all ascending anadromous spawners and descending smolts. We analyzed microsatellite DNA markers from all individuals ascending in 2006-2016, along with all emigrating smolts in 2017. We investigated (1) if there was evidence for declines in census numbers and effective population size during that period, (2) if there was association between kinship and migration timing in smolts and anadromous adults, and (3) to what extent resident trout were parents of outmigrating smolts. RESULTS Census counts of anadromous spawners showed no evidence for a decline from 2006 to 2016, but were lower than in 2000-2005. Estimates of effective population size also showed no trends of declines during the study period. Sibship reconstruction of the 2017 smolt run showed significant association between kinship and migration timing, and a similar association was indicated in anadromous spawners. Parentage assignment of 2017 smolts with ascending anadromous trout as candidate parents, and assuming that unknown parents represented resident trout, showed that 70% of smolts had at least one resident parent and 24% had two resident parents. CONCLUSIONS The results bear evidence of a population that after an initial decline has stabilized at a lower number of anadromous spawners. The significant association between kinship and migration timing in smolts suggests that specific episodes of elevated mortality in the sea could disproportionally affect some families and reduce overall effective population size. Finally, the results based on parentage assignment demonstrate a strong buffering effect of resident trout in case of elevated marine mortality affecting anadromous trout, but also highlight that increased mortality of anadromous trout, most of which are females, may lower overall production in the system.
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Affiliation(s)
- Eloïse Duval
- Department of Biology, Aarhus University, Ny Munkegade 114, 8000, Aarhus C, Denmark.
- Theoretical and Experimental Ecology Station, UMR-5321, CNRS, University of Toulouse III Paul Sabatier, 2 route du CNRS, 09200, Moulis, France.
| | - Øystein Skaala
- Department of Aquaculture, Institute of Marine Research, Nordnes, P.O. Box 1870, 5817, Bergen, Norway.
| | - María Quintela
- Department of Aquaculture, Institute of Marine Research, Nordnes, P.O. Box 1870, 5817, Bergen, Norway
| | - Geir Dahle
- Department of Aquaculture, Institute of Marine Research, Nordnes, P.O. Box 1870, 5817, Bergen, Norway
| | - Aurélien Delaval
- Department of Aquaculture, Institute of Marine Research, Nordnes, P.O. Box 1870, 5817, Bergen, Norway
- Faculty of Biosciences and Aquaculture, Nord University, 8049, Bodø, Norway
| | - Vidar Wennevik
- Department of Aquaculture, Institute of Marine Research, Nordnes, P.O. Box 1870, 5817, Bergen, Norway
| | - Kevin A Glover
- Department of Aquaculture, Institute of Marine Research, Nordnes, P.O. Box 1870, 5817, Bergen, Norway
- Institute of Biology, University of Bergen, Bergen, Norway
| | - Michael M Hansen
- Department of Biology, Aarhus University, Ny Munkegade 114, 8000, Aarhus C, Denmark.
- Department of Aquaculture, Institute of Marine Research, Nordnes, P.O. Box 1870, 5817, Bergen, Norway.
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Fjelldal PG, Hansen TJ, Wargelius A, Ayllon F, Glover KA, Schulz RW, Fraser TWK. Development of supermale and all-male Atlantic salmon to research the vgll3 allele - puberty link. BMC Genet 2020; 21:123. [PMID: 33183224 PMCID: PMC7664053 DOI: 10.1186/s12863-020-00927-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/27/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Farmed Atlantic salmon are one of the most economically significant global aquaculture products. Early sexual maturation of farmed males represents a significant challenge to this industry and has been linked with the vgll3 genotype. However, tools to aid research of this topic, such as all-male and clonal fish, are still lacking. The present 6-year study examined if all-male production is possible in Atlantic salmon, a species with heteromorphic sex chromosomes (males being XY, females XX), and if all-male fish can be applied to further explore the vgll3 contribution on the likelihood of early maturation. RESULTS Estrogen treatment of mixed sex yolk sac larvae gave rise to one sexually mature hermaphrodite with a male genotype (XY) that was used to produce both self-fertilized offspring and androgenetic double haploid (dh) offspring following egg activation with UV treated sperm and pressure shock to block the first mitotic division. There were YY supermales among both offspring types, which were crossed with dh females. Between 1 and 8% of the putative all-male offspring from the eight crosses with self-fertilized supermales were found to have ovaries, and 95% of these phenotypic females were also genetically female. None of the offspring from the one dh supermale cross had ovaries. When assessing the general contribution of the vgll3 locus on the likelihood of early post-smolt sexual maturation (jacking) in the all-male populations we found individuals that were homozygous for the early maturing genotype (97%) were more likely to enter puberty than individuals that were homozygous for the late maturing genotype (26%). However, the likelihood of jacking within individuals with an early/late heterozygous genotype was higher when the early allele came from the dam (94%) compared to the sire (45%). CONCLUSIONS The present results show that supermale Atlantic salmon are viable and fertile and can be used as a research tool to study important aspects of sexual maturation, such as to further explore the sex dependent parental genetic contribution to age at puberty in Atlantic salmon. In addition, we report the production of viable double haploid supermale fish.
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Affiliation(s)
- Per Gunnar Fjelldal
- Institute of Marine Research (IMR), Matre Aquaculture Research Station, 5984 Matredal, Norway
| | - Tom J. Hansen
- Institute of Marine Research (IMR), Matre Aquaculture Research Station, 5984 Matredal, Norway
| | - Anna Wargelius
- Institute of Marine Research (IMR), PO Box 1870, Nordnes, 5817 Bergen, Norway
| | - Fernando Ayllon
- Institute of Marine Research (IMR), PO Box 1870, Nordnes, 5817 Bergen, Norway
| | - Kevin A. Glover
- Institute of Marine Research (IMR), PO Box 1870, Nordnes, 5817 Bergen, Norway
| | - Rüdiger W. Schulz
- Reproductive Biology Group, Division Developmental Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, The Netherlands
| | - Thomas W. K. Fraser
- Institute of Marine Research (IMR), Matre Aquaculture Research Station, 5984 Matredal, Norway
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