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Perry WB, Kaufmann J, Solberg MF, Brodie C, Coral Medina AM, Pillay K, Egerton A, Harvey A, Phillips KP, Coughlan J, Egan F, Grealis R, Hutton S, Leseur F, Ryan S, Poole R, Rogan G, Ryder E, Schaal P, Waters C, Wynne R, Taylor M, Prodöhl P, Creer S, Llewellyn M, McGinnity P, Carvalho G, Glover KA. Domestication-induced reduction in eye size revealed in multiple common garden experiments: The case of Atlantic salmon ( Salmo salar L.). Evol Appl 2021; 14:2319-2332. [PMID: 34603501 PMCID: PMC8477603 DOI: 10.1111/eva.13297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 08/24/2021] [Indexed: 11/28/2022] Open
Abstract
Domestication leads to changes in traits that are under directional selection in breeding programmes, though unintentional changes in nonproduction traits can also arise. In offspring of escaping fish and any hybrid progeny, such unintentionally altered traits may reduce fitness in the wild. Atlantic salmon breeding programmes were established in the early 1970s, resulting in genetic changes in multiple traits. However, the impact of domestication on eye size has not been studied. We measured body size corrected eye size in 4000 salmon from six common garden experiments conducted under artificial and natural conditions, in freshwater and saltwater environments, in two countries. Within these common gardens, offspring of domesticated and wild parents were crossed to produce 11 strains, with varying genetic backgrounds (wild, domesticated, F1 hybrids, F2 hybrids and backcrosses). Size-adjusted eye size was influenced by both genetic and environmental factors. Domesticated fish reared under artificial conditions had smaller adjusted eye size when compared to wild fish reared under identical conditions, in both the freshwater and marine environments, and in both Irish and Norwegian experiments. However, in parr that had been introduced into a river environment shortly after hatching and sampled at the end of their first summer, differences in adjusted eye size observed among genetic groups were of a reduced magnitude and were nonsignificant in 2-year-old sea migrating smolts sampled in the river immediately prior to sea entry. Collectively, our findings could suggest that where natural selection is present, individuals with reduced eye size are maladapted and consequently have reduced fitness, building on our understanding of the mechanisms that underlie a well-documented reduction in the fitness of the progeny of domesticated salmon, including hybrid progeny, in the wild.
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Affiliation(s)
- William Bernard Perry
- Molecular Ecology and Fisheries Genetics LaboratorySchool of Biological ScienceBangor UniversityBangor, GwyneddUK
- Water Research InstituteSchool of BiosciencesCardiff UniversityCardiffUK
- Population Genetics Research GroupInstitute of Marine ResearchBergenNorway
| | - Joshka Kaufmann
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | | | - Christopher Brodie
- Ecosystems and Environment Research CentreSchool of Environment and Life SciencesUniversity of SalfordSalfordUK
| | | | - Kirthana Pillay
- Molecular Ecology and Fisheries Genetics LaboratorySchool of Biological ScienceBangor UniversityBangor, GwyneddUK
| | - Anna Egerton
- Molecular Ecology and Fisheries Genetics LaboratorySchool of Biological ScienceBangor UniversityBangor, GwyneddUK
| | - Alison Harvey
- Population Genetics Research GroupInstitute of Marine ResearchBergenNorway
| | - Karl P. Phillips
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Jamie Coughlan
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
| | - Fintan Egan
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Ronan Grealis
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Steve Hutton
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
| | - Floriane Leseur
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Sarah Ryan
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | | | - Ger Rogan
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Elizabeth Ryder
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Patrick Schaal
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
- Institute of BiodiversityAnimal Health & Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Catherine Waters
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Robert Wynne
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
| | - Martin Taylor
- School of Biological SciencesUniversity of East AngliaNorwichUK
| | - Paulo Prodöhl
- Institute for Global Food SecuritySchool of Biological SciencesMedical Biology CentreQueen’s UniversityBelfastUK
| | - Simon Creer
- Molecular Ecology and Fisheries Genetics LaboratorySchool of Biological ScienceBangor UniversityBangor, GwyneddUK
| | - Martin Llewellyn
- Institute of BiodiversityAnimal Health & Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Philip McGinnity
- School of Biological, Earth and Environmental SciencesUniversity College CorkCorkIreland
- Marine InstituteFurnace, NewportCo. MayoIreland
| | - Gary Carvalho
- Molecular Ecology and Fisheries Genetics LaboratorySchool of Biological ScienceBangor UniversityBangor, GwyneddUK
| | - Kevin Alan Glover
- Population Genetics Research GroupInstitute of Marine ResearchBergenNorway
- Institute of BiologyUniversity of BergenBergenNorway
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Perry WB, Solberg MF, Brodie C, Medina AC, Pillay KG, Egerton A, Harvey A, Creer S, Llewellyn M, Taylor M, Carvalho G, Glover KA. Disentangling the effects of sex, life history and genetic background in Atlantic salmon: growth, heart and liver under common garden conditions. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200811. [PMID: 33204455 PMCID: PMC7657880 DOI: 10.1098/rsos.200811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/17/2020] [Indexed: 06/11/2023]
Abstract
Livestock domestication has long been a part of agriculture, estimated to have first occurred approximately 10 000 years ago. Despite the plethora of traits studied, there is little understanding of the possible impacts domestication has had on internal organs, which are key determinants of survival. Moreover, the genetic basis of observed associated changes in artificial environments is still puzzling. Here we examine impacts of captivity on two organs in Atlantic salmon (Salar salar) that have been domesticated for approximately 50 years: heart and liver, in addition to growth. We studied multiple families of wild, domesticated, F1 and F2 hybrid, and backcrossed strains of S. salar in replicated common garden tanks during the freshwater and marine stages of development. Heart and liver weight were investigated, along with heart morphology metrics examined in just the wild, domesticated and F1 hybrid strains (heart height and width). Growth was positively linked with the proportion of the domesticated strain, and recombination in F2 hybrids (and the potential disruption of co-adapted gene complexes) did not influence growth. Despite the influence of domestication on growth, we found no evidence for domestication-driven divergence in heart or liver morphology. However, sexual dimorphism was detected in heart morphology, and after controlling for body size, females exhibited significantly larger heart weight and heart width when compared with males. Wild females also had an increased heart height when compared with wild males, and this was not observed in any other strain. Females sampled in saltwater showed significantly larger heart height with rounder hearts, than saltwater males. Collectively, these results demonstrate an additive basis of growth and, despite a strong influence of domestication on growth, no clear evidence of changes in heart or liver morphology associated with domestication was identified.
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Affiliation(s)
- William Bernard Perry
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Monica F. Solberg
- Population Genetics Research Group, Institute of Marine Research, PO Box 1870, Nordnes 5817, Bergen, Norway
| | - Christopher Brodie
- Mariani Molecular Ecology Laboratory, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool L3 5UX, UK
| | - Angela C. Medina
- School of Microbiology, Food Science and Technology Building University College Cork, Cork T12 TP07, Ireland
| | - Kirthana G. Pillay
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Anna Egerton
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Alison Harvey
- Population Genetics Research Group, Institute of Marine Research, PO Box 1870, Nordnes 5817, Bergen, Norway
| | - Simon Creer
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Martin Llewellyn
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Martin Taylor
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Gary Carvalho
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Kevin A. Glover
- Population Genetics Research Group, Institute of Marine Research, PO Box 1870, Nordnes 5817, Bergen, Norway
- Institute of Biology, University of Bergen, Bergen, Norway
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Harvey AC, Skilbrei OT, Besnier F, Solberg MF, Sørvik AGE, Glover KA. Implications for introgression: has selection for fast growth altered the size threshold for precocious male maturation in domesticated Atlantic salmon? BMC Evol Biol 2018; 18:188. [PMID: 30558529 PMCID: PMC6298023 DOI: 10.1186/s12862-018-1294-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 11/16/2018] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Mature male parr (MMP) represent an important alternative life-history strategy in Atlantic salmon populations. Previous studies indicate that the maturation size threshold for male parr varies among wild populations and is influenced by individual growth, environmental conditions, and genetics. More than ten generations of breeding have resulted in domesticated salmon displaying many genetic differences to wild salmon, including greatly increased growth rates. This may have resulted in domesticated fish with the potential to outgrow the size threshold for early maturation, or evolution of the size threshold of the trait itself. To investigate this, we performed a common-garden experiment under farming conditions using 4680 salmon from 39 families representing four wild, two wild-domesticated hybrid, and two domesticated strains. RESULTS Domesticated salmon outgrew wild salmon 2-5-fold, and hybrids displayed intermediate growth. Overall, the numbers of MMP varied greatly among families and strains: averaging 4-12% in domesticated, 18-25% in hybrid, and 43-74% in the wild populations. However, when the influence of growth was accounted for, by dividing fish into lower and upper size modes, no difference in the incidence of MMP was detected among domesticated and wild strains in either size mode. In the lower size mode, hybrids displayed significantly lower incidences of mature males than their wild parental strains. No consistent differences in the body size of MMP, connected to domestication, was detected. CONCLUSIONS Our data demonstrate: 1- no evidence for the evolution of the size threshold for MMP in domesticated salmon, 2- the vastly lower incidence of MMP in domesticated strains under aquaculture conditions is primarily due to their genetically increased growth rate causing them to outgrow the size threshold for early maturation, 3- the incidence of MMP is likely to overlap among domesticated and wild salmon in the natural habitat where they typically display overlapping growth, although hybrid offspring may display lower incidences of mature male parr. These results have implications for wild salmon populations that are exposed to introgression from domesticated escapees.
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Affiliation(s)
- A C Harvey
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway.
| | - O T Skilbrei
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - F Besnier
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - M F Solberg
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - A-G E Sørvik
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - K A Glover
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway.,Department of Biology, University of Bergen, P. O. Box 7803, N-5020, Bergen, Norway
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Glover KA, Solberg MF, Besnier F, Skaala Ø. Cryptic introgression: evidence that selection and plasticity mask the full phenotypic potential of domesticated Atlantic salmon in the wild. Sci Rep 2018; 8:13966. [PMID: 30228303 PMCID: PMC6143624 DOI: 10.1038/s41598-018-32467-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/03/2018] [Indexed: 01/13/2023] Open
Abstract
Domesticated Atlantic salmon grow much faster than wild salmon when reared together in fish tanks under farming conditions (size ratios typically 1:2-3). In contrast, domesticated salmon only display marginally higher growth than wild salmon when reared together in rivers (size ratios typically 1:1-1.2). This begs the question why? Is this a difference in the plastic response driven by divergent energy budgets between the two environments, or is it a result of selection, whereby domesticated salmon that display the greatest growth-potential are those at greatest risk of mortality in the wild? We reared domesticated, hybrid and wild salmon in a river until they smoltified at age 2 or 4, and thereafter in fish tanks for a further 2 years. In the river, there was no difference in the mean size between the groups. In contrast, after being transferred from the river to fish tanks, the domesticated salmon significantly outgrew the wild salmon (maximum size ratio of ~1:1.8). This demonstrates that selection alone cannot be responsible for the lack of growth differences observed between domesticated and wild salmon in rivers. Nevertheless, the final size ratios observed after rearing in tanks were lower than expected in that environment, thus suggesting that plasticity, as for selection, cannot be the sole mechanism. We therefore conclude that a combination of energy-budget plasticity, and selection via growth-potential mortality, cause the differences in growth reaction norms between domesticated and wild salmon across these contrasting environments. Our results imply that if phenotypic changes are not observed in wild populations following introgression of domesticated conspecifics, it does not mean that functional genetic changes have not occurred in the admixed population. Clearly, under the right environmental conditions, the underlying genetic changes will manifest themselves in the phenotype.
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Affiliation(s)
- Kevin A Glover
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway. .,University of Bergen, Department of Biology, P.O. Box 7803, N-5020, Bergen, Norway.
| | - Monica F Solberg
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway
| | - Francois Besnier
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway
| | - Øystein Skaala
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway
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Harvey AC, Fjelldal PG, Solberg MF, Hansen T, Glover KA. Ploidy elicits a whole-genome dosage effect: growth of triploid Atlantic salmon is linked to the genetic origin of the second maternal chromosome set. BMC Genet 2017; 18:34. [PMID: 28399816 PMCID: PMC5387229 DOI: 10.1186/s12863-017-0502-x] [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: 12/16/2016] [Accepted: 04/06/2017] [Indexed: 12/30/2022] Open
Abstract
Background The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid performance often show contrasting results. Studies have identified dosage and dosage-compensation effects for gene expression between triploid and diploid salmonids, but no study has investigated how ploidy and parent-origin effects interact on a polygenic trait in divergent lines of Atlantic salmon (i.e. slow growing wild versus fast growing domesticated phenotype). This study utilised two experiments relating to the freshwater growth of diploid and triploid groups of pure wild (0% domesticated genome), pure domesticated (100% domesticated genome), and F1 reciprocal hybrid (33%, 50% or 66% domesticated genome) salmon where triploidy was either artificially induced (experiment 1) or naturally developed/spontaneous (experiment 2). Results In both experiments, reciprocal hybrid growth was influenced by the dosage effect of the second maternal chromosome, with growth increasing as ploidy level increased in individuals with a domesticated dam (from 50% to 66% domesticated genome), and the inverse in individuals with a wild dam (from 50% to 33% domesticated genome). Conclusions We demonstrate that the combined effect of ploidy and parent-origin on growth, a polygenic trait, is regulated in an additive pattern. Therefore, in order to maximise growth potential, the aquaculture industry should consider placing more emphasis on the breeding value of the dam than the sire when producing triploid families for commercial production. Electronic supplementary material The online version of this article (doi:10.1186/s12863-017-0502-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- A C Harvey
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway.
| | - P G Fjelldal
- Institute of Marine Research (IMR), Matre Research Station, NO-5984, Matredal, Norway
| | - M F Solberg
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - T Hansen
- Institute of Marine Research (IMR), Matre Research Station, NO-5984, Matredal, Norway
| | - K A Glover
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway.,Department of Biology, University of Bergen, P. O. Box 7803, N-5020, Bergen, Norway
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