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Hale MC, Pearse DE, Campbell MA. Characterization and distribution of a 14-Mb chromosomal inversion in native populations of rainbow trout (Oncorhynchus mykiss). G3 (BETHESDA, MD.) 2024; 14:jkae100. [PMID: 38885060 PMCID: PMC11228831 DOI: 10.1093/g3journal/jkae100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/10/2024] [Indexed: 06/20/2024]
Abstract
Multiple studies in a range of taxa have found links between structural variants and the development of ecologically important traits. Such variants are becoming easier to find due, in large part, to the increase in the amount of genome-wide sequence data in nonmodel organisms. The salmonids (salmon, trout, and charr) are a taxonomic group with abundant genome-wide datasets due to their importance in aquaculture, fisheries, and variation in multiple ecologically important life-history traits. Previous research on rainbow trout (Oncorhynchus mykiss) has documented a large pericentric (∼55 Mb) chromosomal inversion (CI) on chromosome 5 (Omy05) and a second smaller (∼14 Mb) chromosome inversion on Omy20. While the Omy05 inversion appears to be associated with multiple adaptive traits, the inversion on Omy20 has received far less attention. In this study, we re-analyze RAD-seq and amplicon data from several populations of rainbow trout (O. mykiss) to better document the structure and geographic distribution of variation in the Omy20 CI. Moreover, we utilize phylogenomic techniques to characterize both the age- and the protein-coding gene content of the Omy20 CI. We find that the age of the Omy20 inversion dates to the early stages of O. mykiss speciation and predates the Omy05 inversion by ∼450,000 years. The 2 CIs differ further in terms of the frequency of the homokaryotypes. While both forms of the Omy05 CI are found across the eastern Pacific, the ancestral version of the Omy20 CI is restricted to the southern portion of the species range in California. Furthermore, the Omy20 inverted haplotype is comparable in genetic diversity to the ancestral form, whereas derived CIs typically show substantially reduced genetic diversity. These data contribute to our understanding of the age and distribution of a large CI in rainbow trout and provide a framework for researchers looking to document CIs in other nonmodel species.
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Affiliation(s)
- Matthew C Hale
- Department of Biology, Texas Christian University, Fort Worth, TX 76109, USA
| | - Devon E Pearse
- Southwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Santa Cruz, CA 95064, USA
| | - Matthew A Campbell
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
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2
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Kess T, Lehnert SJ, Bentzen P, Duffy S, Messmer A, Dempson JB, Newport J, Whidden C, Robertson MJ, Chaput G, Breau C, April J, Gillis C, Kent M, Nugent CM, Bradbury IR. Variable parallelism in the genomic basis of age at maturity across spatial scales in Atlantic Salmon. Ecol Evol 2024; 14:e11068. [PMID: 38584771 PMCID: PMC10995719 DOI: 10.1002/ece3.11068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Accepted: 01/31/2024] [Indexed: 04/09/2024] Open
Abstract
Complex traits often exhibit complex underlying genetic architectures resulting from a combination of evolution from standing variation, hard and soft sweeps, and alleles of varying effect size. Increasingly, studies implicate both large-effect loci and polygenic patterns underpinning adaptation, but the extent that common genetic architectures are utilized during repeated adaptation is not well understood. Sea age or age at maturation represents a significant life history trait in Atlantic Salmon (Salmo salar), the genetic basis of which has been studied extensively in European Atlantic populations, with repeated identification of large-effect loci. However, the genetic basis of sea age within North American Atlantic Salmon populations remains unclear, as does the potential for a parallel trans-Atlantic genomic basis to sea age. Here, we used a large single-nucleotide polymorphism (SNP) array and low-coverage whole-genome resequencing to explore the genomic basis of sea age variation in North American Atlantic Salmon. We found significant associations at the gene and SNP level with a large-effect locus (vgll3) previously identified in European populations, indicating genetic parallelism, but found that this pattern varied based on both sex and geographic region. We also identified nonrepeated sets of highly predictive loci associated with sea age among populations and sexes within North America, indicating polygenicity and low rates of genomic parallelism. Despite low genome-wide parallelism, we uncovered a set of conserved molecular pathways associated with sea age that were consistently enriched among comparisons, including calcium signaling, MapK signaling, focal adhesion, and phosphatidylinositol signaling. Together, our results indicate parallelism of the molecular basis of sea age in North American Atlantic Salmon across large-effect genes and molecular pathways despite population-specific patterns of polygenicity. These findings reveal roles for both contingency and repeated adaptation at the molecular level in the evolution of life history variation.
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Affiliation(s)
- Tony Kess
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Sarah J. Lehnert
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Paul Bentzen
- Department of BiologyDalhousie UniversityHalifaxNova ScotiaCanada
| | - Steven Duffy
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Amber Messmer
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - J. Brian Dempson
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Jason Newport
- Marine Environmental Research Infrastructure for Data Integration and Application NetworkHalifaxNova ScotiaCanada
| | | | - Martha J. Robertson
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Gerald Chaput
- Fisheries and Oceans CanadaGulf Fisheries CentreMonctonNew BrunswickCanada
| | - Cindy Breau
- Fisheries and Oceans CanadaGulf Fisheries CentreMonctonNew BrunswickCanada
| | - Julien April
- Ministère des Forêts de la Faune et des ParcsQuebecQuebecCanada
| | - Carole‐Anne Gillis
- Gespe'gewa'gi, Mi'gma'qi, ListugujGespe'gewa'gi Institute of Natural UnderstandingQuebecQuebecCanada
| | - Matthew Kent
- Centre for Integrative GeneticsNorwegian University of Life SciencesÅsNorway
| | - Cameron M. Nugent
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Ian R. Bradbury
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
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3
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Lecomte L, Árnyasi M, Ferchaud A, Kent M, Lien S, Stenløkk K, Sylvestre F, Bernatchez L, Mérot C. Investigating structural variant, indel and single nucleotide polymorphism differentiation between locally adapted Atlantic salmon populations. Evol Appl 2024; 17:e13653. [PMID: 38495945 PMCID: PMC10940791 DOI: 10.1111/eva.13653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 12/14/2023] [Accepted: 01/13/2024] [Indexed: 03/19/2024] Open
Abstract
Genomic structural variants (SVs) are now recognized as an integral component of intraspecific polymorphism and are known to contribute to evolutionary processes in various organisms. However, they are inherently difficult to detect and genotype from readily available short-read sequencing data, and therefore remain poorly documented in wild populations. Salmonid species displaying strong interpopulation variability in both life history traits and habitat characteristics, such as Atlantic salmon (Salmo salar), offer a prime context for studying adaptive polymorphism, but the contribution of SVs to fine-scale local adaptation has yet to be explored. Here, we performed a comparative analysis of SVs, single nucleotide polymorphisms (SNPs) and small indels (<50 bp) segregating in the Romaine and Puyjalon salmon, two putatively locally adapted populations inhabiting neighboring rivers (Québec, Canada) and showing pronounced variation in life history traits, namely growth, fecundity, and age at maturity and smoltification. We first catalogued polymorphism using a hybrid SV characterization approach pairing both short- (16X) and long-read sequencing (20X) for variant discovery with graph-based genotyping of SVs across 60 salmon genomes, along with characterization of SNPs and small indels from short reads. We thus identified 115,907 SVs, 8,777,832 SNPs and 1,089,321 short indels, with SVs covering 4.8 times more base pairs than SNPs. All three variant types revealed a highly congruent population structure and similar patterns of F ST and density variation along the genome. Finally, we performed outlier detection and redundancy analysis (RDA) to identify variants of interest in the putative local adaptation of Romaine and Puyjalon salmon. Genes located near these variants were enriched for biological processes related to nervous system function, suggesting that observed variation in traits such as age at smoltification could arise from differences in neural development. This study therefore demonstrates the feasibility of large-scale SV characterization and highlights its relevance for salmonid population genomics.
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Affiliation(s)
- Laurie Lecomte
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
- Département de BiologieUniversité LavalQuébecCanada
| | - Mariann Árnyasi
- Department of Animal and Aquacultural Sciences (IHA), Faculty of Life Sciences (BIOVIT), Centre for Integrative Genetics (CIGENE)Norwegian University of Life Sciences (NMBU)ÅsNorway
| | - Anne‐Laure Ferchaud
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
- Département de BiologieUniversité LavalQuébecCanada
- Present address:
Parks Canada, Office of the Chief Ecosystem ScientistQuébecQCCanada
| | - Matthew Kent
- Department of Animal and Aquacultural Sciences (IHA), Faculty of Life Sciences (BIOVIT), Centre for Integrative Genetics (CIGENE)Norwegian University of Life Sciences (NMBU)ÅsNorway
| | - Sigbjørn Lien
- Department of Animal and Aquacultural Sciences (IHA), Faculty of Life Sciences (BIOVIT), Centre for Integrative Genetics (CIGENE)Norwegian University of Life Sciences (NMBU)ÅsNorway
| | - Kristina Stenløkk
- Department of Animal and Aquacultural Sciences (IHA), Faculty of Life Sciences (BIOVIT), Centre for Integrative Genetics (CIGENE)Norwegian University of Life Sciences (NMBU)ÅsNorway
| | - Florent Sylvestre
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
- Département de BiologieUniversité LavalQuébecCanada
| | - Louis Bernatchez
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
- Département de BiologieUniversité LavalQuébecCanada
| | - Claire Mérot
- Institut de Biologie Intégrative et des Systèmes (IBIS)Université LavalQuébecCanada
- Département de BiologieUniversité LavalQuébecCanada
- Present address:
UMR 6553 Ecobio, OSUR, CNRSUniversité de RennesRennesFrance
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4
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Souza LHB, Pierson TW, Tenório RO, Ferro JM, Gatto KP, Silva BC, de Andrade GV, Suárez P, Haddad CFB, Lourenço LB. Multiple contact zones and karyotypic evolution in a neotropical frog species complex. Sci Rep 2024; 14:1119. [PMID: 38212602 PMCID: PMC10784582 DOI: 10.1038/s41598-024-51421-z] [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: 07/10/2023] [Accepted: 01/04/2024] [Indexed: 01/13/2024] Open
Abstract
Previous studies of DNA sequence and karyotypic data have revealed high genetic diversity in the Physalaemus cuvieri - Physalaemus ephippifer species complex-a group of small leptodactylid frogs in South America. To date, seven major genetic lineages have been recognized in this group, with species delimitation tests supporting four to seven of them as valid species. Among these, only P. ephippifer shows heteromorphic sex chromosomes, but the implications of cytogenetic divergence for the evolution of this group are unknown. We analyzed karyotypic, mitochondrial DNA, and 3RAD genomic data to characterize a putative contact zone between P. ephippifer and P. cuvieri Lineage 1, finding evidence for admixture and karyotypic evolution. We also describe preliminary evidence for admixture between two other members of this species complex-Lineage 1 and Lineage 3 of P. cuvieri. Our study sheds new light on evolutionary relationships in the P. cuvieri - P. ephippifer species complex, suggesting an important role of karyotypic divergence in its evolutionary history and underscoring the importance of hybridization as a mechanism of sex chromosome evolution in amphibians.
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Affiliation(s)
- Lucas H B Souza
- Laboratório de Estudos Cromossômicos (LabEsC), Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, 13083-863, Brazil.
| | - Todd W Pierson
- Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, Kennesaw, GA, USA
| | - Renata O Tenório
- Laboratório de Estudos Cromossômicos (LabEsC), Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, 13083-863, Brazil
| | - Juan M Ferro
- Laboratorio de Genética Evolutiva "Dr. Claudio J. Bidau", Instituto de Biología Subtropical (CONICET-UNaM), Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Posadas, Misiones, Argentina
| | - Kaleb P Gatto
- Laboratório de Estudos Cromossômicos (LabEsC), Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, 13083-863, Brazil
| | - Bruno C Silva
- Laboratório de Estudos Cromossômicos (LabEsC), Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, 13083-863, Brazil
| | - Gilda V de Andrade
- Departamento de Biologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal do Maranhão (UFMA), Campus do Bacanga, São Luís, MA, 65080-040, Brazil
| | - Pablo Suárez
- Instituto de Biología Subtropical (CONICET-UNaM), Puerto Iguazú, Argentina
| | - Célio F B Haddad
- Departamento de Biodiversidade and Centro de Aquicultura (CAUNESP), Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, SP, Brazil
| | - Luciana B Lourenço
- Laboratório de Estudos Cromossômicos (LabEsC), Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, 13083-863, Brazil
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5
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Lehnert SJ, Bradbury IR, Wringe BF, Van Wyngaarden M, Bentzen P. Multifaceted framework for defining conservation units: An example from Atlantic salmon ( Salmo salar) in Canada. Evol Appl 2023; 16:1568-1585. [PMID: 37752960 PMCID: PMC10519414 DOI: 10.1111/eva.13587] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/12/2023] [Accepted: 07/26/2023] [Indexed: 09/28/2023] Open
Abstract
Conservation units represent important components of intraspecific diversity that can aid in prioritizing and protecting at-risk populations, while also safeguarding unique diversity that can contribute to species resilience. In Canada, identification and assessments of conservation units is done by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). COSEWIC can recognize conservation units below the species level (termed "designatable units"; DUs) if the unit has attributes that make it both discrete and evolutionarily significant. There are various ways in which a DU can meet criteria of discreteness and significance, and increasing access to "big data" is providing unprecedented information that can directly inform both criteria. Specifically, the incorporation of genomic data for an increasing number of non-model species is informing more COSEWIC assessments; thus, a repeatable, robust framework is needed for integrating these data into DU characterization. Here, we develop a framework that uses a multifaceted, weight of evidence approach to incorporate multiple data types, including genetic and genomic data, to inform COSEWIC DUs. We apply this framework to delineate DUs of Atlantic salmon (Salmo salar, L.), an economically, culturally, and ecologically significant species, that is also characterized by complex hierarchical population structure. Specifically, we focus on an in-depth example of how our approach was applied to a previously data limited region of northern Canada that was defined by a single large DU. Application of our framework with newly available genetic and genomic data led to subdividing this DU into three new DUs. Although our approach was developed to meet criteria of COSEWIC, it is widely applicable given similarities in the definitions of a conservation unit.
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Affiliation(s)
- Sarah J. Lehnert
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Ian R. Bradbury
- Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Brendan F. Wringe
- Bedford Institute of OceanographyFisheries and Oceans CanadaDartmouthNova ScotiaCanada
| | | | - Paul Bentzen
- Biology DepartmentDalhousie UniversityHalifaxNova ScotiaCanada
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6
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Gao G, Waldbieser GC, Youngblood RC, Zhao D, Pietrak MR, Allen MS, Stannard JA, Buchanan JT, Long RL, Milligan M, Burr G, Mejía-Guerra K, Sheehan MJ, Scheffler BE, Rexroad CE, Peterson BC, Palti Y. The generation of the first chromosome-level de novo genome assembly and the development and validation of a 50K SNP array for the St. John River aquaculture strain of North American Atlantic salmon. G3 (BETHESDA, MD.) 2023; 13:jkad138. [PMID: 37335943 PMCID: PMC10468304 DOI: 10.1093/g3journal/jkad138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/21/2023]
Abstract
Atlantic salmon (Salmo salar) in Northeastern US and Eastern Canada has high economic value for the sport fishing and aquaculture industries. Large differences exist between the genomes of Atlantic salmon of European origin and North American (N.A.) origin. Given the genetic and genomic differences between the 2 lineages, it is crucial to develop unique genomic resources for N.A. Atlantic salmon. Here, we describe the resources that we recently developed for genomic and genetic research in N.A. Atlantic salmon aquaculture. Firstly, a new single nucleotide polymorphism (SNP) database for N.A. Atlantic salmon consisting of 3.1 million putative SNPs was generated using data from whole-genome resequencing of 80 N.A. Atlantic salmon individuals. Secondly, a high-density 50K SNP array enriched for the genic regions of the genome and containing 3 sex determination and 61 putative continent of origin markers was developed and validated. Thirdly, a genetic map composed of 27 linkage groups with 36K SNP markers was generated from 2,512 individuals in 141 full-sib families. Finally, a chromosome-level de novo genome assembly from a male N.A. Atlantic salmon from the St. John River aquaculture strain was generated using PacBio long reads. Information from Hi-C proximity ligation sequences and Bionano optical mapping was used to concatenate the contigs into scaffolds. The assembly contains 1,755 scaffolds and only 1,253 gaps, with a total length of 2.83 Gb and N50 of 17.2 Mb. A BUSCO analysis detected 96.2% of the conserved Actinopterygii genes in the assembly, and the genetic linkage information was used to guide the formation of 27 chromosome sequences. Comparative analysis with the reference genome assembly of the European Atlantic salmon confirmed that the karyotype differences between the 2 lineages are caused by a fission in chromosome Ssa01 and 3 chromosome fusions including the p arm of chromosome Ssa01 with Ssa23, Ssa08 with Ssa29, and Ssa26 with Ssa28. The genomic resources we have generated for Atlantic salmon provide a crucial boost for genetic research and for management of farmed and wild populations in this highly valued species.
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Affiliation(s)
- Guangtu Gao
- USDA-ARS National Center for Cool and Cold Water Aquaculture, 11861 Leetown Road, Kearneysville, WV 25430, USA
| | - Geoffrey C Waldbieser
- USDA-ARS Warmwater Aquaculture Research Unit, 141 Experimental Station Road, Stoneville, MS 38776, USA
| | - Ramey C Youngblood
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS 39762, USA
| | - Dongyan Zhao
- Breeding Insight, 119 CALS Surge Facility, Cornell University, 525 Tower Road, Ithaca, NY 14853, USA
| | - Michael R Pietrak
- USDA-ARS National Cold Water Marine Aquaculture Center, 25 Salmon Farm Road, Franklin, ME 04634, USA
| | - Melissa S Allen
- Center for Aquaculture Technologies, 8395 Camino Santa Fe, San Diego, CA 92121, USA
| | - Jason A Stannard
- Center for Aquaculture Technologies, 8395 Camino Santa Fe, San Diego, CA 92121, USA
| | - John T Buchanan
- Center for Aquaculture Technologies, 8395 Camino Santa Fe, San Diego, CA 92121, USA
| | - Roseanna L Long
- USDA-ARS National Center for Cool and Cold Water Aquaculture, 11861 Leetown Road, Kearneysville, WV 25430, USA
| | - Melissa Milligan
- USDA-ARS National Cold Water Marine Aquaculture Center, 25 Salmon Farm Road, Franklin, ME 04634, USA
| | - Gary Burr
- USDA-ARS National Cold Water Marine Aquaculture Center, 25 Salmon Farm Road, Franklin, ME 04634, USA
| | - Katherine Mejía-Guerra
- Breeding Insight, 119 CALS Surge Facility, Cornell University, 525 Tower Road, Ithaca, NY 14853, USA
| | - Moira J Sheehan
- Breeding Insight, 119 CALS Surge Facility, Cornell University, 525 Tower Road, Ithaca, NY 14853, USA
| | - Brian E Scheffler
- USDA-ARS Genomics and Bioinformatics Research Unit, 141 Experimental Station Road, Stoneville, MS 38776, USA
| | - Caird E Rexroad
- USDA-ARS Office of National Programs, George Washington Carver Center Room 4-2106, 5601 Sunnyside Avenue, Beltsville, MD 20705, USA
| | - Brian C Peterson
- USDA-ARS National Cold Water Marine Aquaculture Center, 25 Salmon Farm Road, Franklin, ME 04634, USA
| | - Yniv Palti
- USDA-ARS National Center for Cool and Cold Water Aquaculture, 11861 Leetown Road, Kearneysville, WV 25430, USA
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7
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Nugent CM, Kess T, Brachmann MK, Langille BL, Holborn MK, Beck SV, Smith N, Duffy SJ, Lehnert SJ, Wringe BF, Bentzen P, Bradbury IR. Genomic and machine learning-based screening of aquaculture-associated introgression into at-risk wild North American Atlantic salmon (Salmo salar) populations. Mol Ecol Resour 2023. [PMID: 37246351 DOI: 10.1111/1755-0998.13811] [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: 11/23/2022] [Revised: 04/27/2023] [Accepted: 05/02/2023] [Indexed: 05/30/2023]
Abstract
The negative genetic impacts of gene flow from domestic to wild populations can be dependent on the degree of domestication and exacerbated by the magnitude of pre-existing genetic differences between wild populations and the domestication source. Recent evidence of European ancestry within North American aquaculture Atlantic salmon (Salmo salar) has elevated the potential impact of escaped farmed salmon on often at-risk wild North American salmon populations. Here, we compare the ability of single nucleotide polymorphism (SNP) and microsatellite (SSR) marker panels of different sizes (7-SSR, 100-SSR and 220K-SNP) to detect introgression of European genetic information into North American wild and aquaculture populations. Linear regression comparing admixture predictions for a set of individuals common to the three datasets showed that the 100-SSR panel and 7-SSR panels replicated the full 220K-SNP-based admixture estimates with low accuracy (r2 of .64 and .49, respectively). Additional tests explored the effects of individual sample size and marker number, which revealed that ~300 randomly selected SNPs could replicate the 220K-SNP admixture predictions with greater than 95% fidelity. We designed a custom SNP panel (301-SNP) for European admixture detection in future monitoring work and then developed and tested a python package, salmoneuadmix (https://github.com/CNuge/SalmonEuAdmix), which uses a deep neural network to make de novo estimates of individuals' European admixture proportion without the need to conduct complete admixture analysis utilizing baseline samples. The results demonstrate the mobilization of targeted SNP panels and machine learning in support of at-risk species conservation and management.
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Affiliation(s)
- Cameron M Nugent
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
| | - Tony Kess
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
| | - Matthew K Brachmann
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
| | - Barbara L Langille
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
| | - Melissa K Holborn
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - Samantha V Beck
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
- Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada
- Institute for Biodiversity and Freshwater Conservation, University of the Highlands and Islands, Inverness, UK
| | - Nicole Smith
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
| | - Steven J Duffy
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
| | - Sarah J Lehnert
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
| | - Brendan F Wringe
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - Paul Bentzen
- Biology Department, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ian R Bradbury
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, Newfoundland and Labrador, Canada
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8
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Bradbury IR, Lehnert SJ, Kess T, Van Wyngaarden M, Duffy S, Messmer A, Wringe B, Karoliussen S, Dempson JB, Fleming IA, Solberg MF, Glover KA, Bentzen P. Genomic evidence of recent European introgression into North American farmed and wild Atlantic Salmon. Evol Appl 2022; 15:1436-1448. [PMID: 36187183 PMCID: PMC9488674 DOI: 10.1111/eva.13454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/10/2022] [Accepted: 07/08/2022] [Indexed: 12/02/2022] Open
Abstract
Gene flow between wild and domestic populations has been repeatedly demonstrated across a diverse range of taxa. Ultimately, the genetic impacts of gene flow from domestic into wild populations depend both on the degree of domestication and the original source of the domesticated population. Atlantic salmon, Salmo salar, used in North American aquaculture are ostensibly of North American origin. However, evidence of European introgression into North American aquaculture salmon has accumulated in recent decades, even though the use of diploid European salmon has never been approved in Canada. The full extent of such introgression as well as the potential impacts on wild salmon in the Northwest Atlantic remains uncertain. Here, we extend previous work comparing North American and European wild salmon (n = 5799) using a 220 K SNP array to quantify levels of recent European introgression into samples of domestic salmon, aquaculture escapees, and wild salmon collected throughout Atlantic Canada. Analysis of North American farmed salmon (n = 403) and escapees (n = 289) displayed significantly elevated levels of European ancestry by comparison with wild individuals (p < 0.001). Of North American farmed salmon sampled between 2011 and 2018, ~17% had more than 10% European ancestry and several individuals exceeded 40% European ancestry. Samples of escaped farmed salmon similarly displayed elevated levels of European ancestry, with two individuals classified as 100% European. Analysis of juvenile salmon collected in rivers proximate to aquaculture locations also revealed evidence of elevated European ancestry and larger admixture tract in comparison to individuals collected at distance from aquaculture. Overall, our results demonstrate that even though diploid European salmon have never been approved for use in Canada, individuals of full and partial European ancestry have been in use over the last decade, and that some of these individuals have escaped and hybridized in the wild.
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Affiliation(s)
- I. R. Bradbury
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd St. John’s, Newfoundland, A1C 5X1 Canada
| | - S. J. Lehnert
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd St. John’s, Newfoundland, A1C 5X1 Canada
| | - T. Kess
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd St. John’s, Newfoundland, A1C 5X1 Canada
| | - M. Van Wyngaarden
- Biology Department Dalhousie University 1355 Oxford Street Halifax Nova Scotia
| | - S. Duffy
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd St. John’s, Newfoundland, A1C 5X1 Canada
| | - A. Messmer
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd St. John’s, Newfoundland, A1C 5X1 Canada
| | - B. Wringe
- Bedford Institute of Oceanography Fisheries and Oceans Canada Dartmouth NS Canada
| | - S. Karoliussen
- Centre for Integrative Genetics Norwegian University of Life Sciences Ås Norway
| | - J. B. Dempson
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd St. John’s, Newfoundland, A1C 5X1 Canada
| | - I. A. Fleming
- Department of Ocean Sciences, Ocean Sciences Centre Memorial University of Newfoundland St John’s, NL, A1C 5S7 Canada
| | - M. F. Solberg
- Institute of Marine Research Population Genetics Research Group PO Box 1870, Nordnes, N‐5817 Bergen Norway
| | - K. A. Glover
- Institute of Marine Research Population Genetics Research Group PO Box 1870, Nordnes, N‐5817 Bergen Norway
- Department of Biological Sciences University of Bergen N‐5020 Bergen Norway
| | - P. Bentzen
- Biology Department Dalhousie University 1355 Oxford Street Halifax Nova Scotia
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9
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Brachmann MK, Parsons K, Skúlason S, Gaggiotti O, Ferguson M. Variation in the genomic basis of parallel phenotypic and ecological divergence in benthic and pelagic morphs of Icelandic Arctic charr (Salvelinus alpinus). Mol Ecol 2022; 31:4688-4706. [PMID: 35861579 DOI: 10.1111/mec.16625] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 06/22/2022] [Accepted: 07/06/2022] [Indexed: 11/28/2022]
Abstract
Sympatric adaptive phenotypic divergence should be underlain by genomic differentiation between sub-populations. When divergence drives similar patterns of phenotypic and ecological variation within species we expect evolution to draw on common allelic variation. We investigated divergence histories and genomic signatures of adaptive divergence between benthic and pelagic morphs of Icelandic Arctic charr. Divergence histories for each of four populations were reconstructed using coalescent modelling and 14,187 single nucleotide polymorphisms. Sympatric divergence with continuous gene flow was supported in two populations while allopatric divergence with secondary contact was supported in one population; we could not differentiate between demographic models in the fourth population. We detected parallel patterns of phenotypic divergence along benthic-pelagic evolutionary trajectories among populations. Patterns of genomic differentiation between benthic and pelagic morphs were characterized by outlier loci in many narrow peaks of differentiation throughout the genome, which may reflect the eroding effects of gene flow on nearby neutral loci. We then used genome-wide association analyses to relate both phenotypic (body shape and size) and ecological (carbon and nitrogen stable isotopes) variation to patterns of genomic differentiation. Many peaks of genomic differentiation were associated with phenotypic and ecological variation in the three highly divergent populations, suggesting a genomic basis for adaptive divergence. We detected little evidence for a parallel genomic basis of differentiation as most regions and outlier loci were not shared among populations. Our results show that adaptive divergence can have varied genomic consequences in populations with relatively recent common origins, similar divergence histories, and parallel phenotypic divergence.
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Affiliation(s)
| | - Kevin Parsons
- Institute of Biodiversity, Animal Health and Comparative Medicine, School of Life Science, University of Glasgow, Glasgow, UK
| | - Skúli Skúlason
- Department of Aquaculture and Fish Biology, Hólar University, Saudárkrókur, Iceland.,Icelandic Museum of Natural History, Reykjavik, Iceland
| | - Oscar Gaggiotti
- School of biology, Scottish Oceans Institute, University of St. Andrews, St. Andrews, UK
| | - Moira Ferguson
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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10
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Islam SS, Xue X, Caballero-Solares A, Bradbury IR, Rise ML, Fleming IA. Distinct early life stage gene expression effects of hybridization among European and North American farmed and wild Atlantic salmon populations. Mol Ecol 2022; 31:2712-2729. [PMID: 35243721 DOI: 10.1111/mec.16418] [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: 09/20/2021] [Revised: 01/29/2022] [Accepted: 02/21/2022] [Indexed: 11/27/2022]
Abstract
Due to multi-generation domestication selection, farmed and wild Atlantic salmon diverge genetically, which raises concerns about potential genetic interactions among escaped farmed and wild populations and disruption of local adaptation through introgression. When farmed strains of distant geographic origin are used, it is unknown whether the genetic consequences posed by escaped farmed fish will be greater than if more locally derived strains are used. Quantifying gene transcript expression differences among divergent farmed, wild and F1 hybrids under controlled conditions is one of the ways to explore the consequences of hybridization. We compared the transcriptomes of fry at the end of yolk sac absorption of a European (EO) farmed ("StofnFiskur", Norwegian strain), a North American (NA) farmed (Saint John River, NB strain), a Newfoundland (NF) wild population with EO ancestry, and related F1 hybrids using 44K microarrays. Our findings indicate that the wild population showed greater transcriptome differences from the EO farmed strain than that of the NA farmed strain. We also found the largest differences in global gene expression between the two farmed strains. We detected the fewest differentially expressed transcripts between F1 hybrids and domesticated/wild maternal strains. We also found that the differentially expressed genes between cross types over-represented GO terms associated with metabolism, development, growth, immune response, and redox homeostasis processes. These findings suggest that the interbreeding of escaped EO/NA farmed and NF wild population would alter gene transcription, and the consequences of hybridization would be greater from escaped EO farmed than NA farmed salmon, resulting in potential effects on the wild populations.
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Affiliation(s)
- Shahinur S Islam
- Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, A1C 5S7, Canada
| | - Xi Xue
- Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, A1C 5S7, Canada
| | - Albert Caballero-Solares
- Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, A1C 5S7, Canada
| | - Ian R Bradbury
- Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, A1C 5S7, Canada.,Salmonids Section, Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 East White Hills Road, St. John's, NL, A1C 5X, Canada
| | - Matthew L Rise
- Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, A1C 5S7, Canada
| | - Ian A Fleming
- Department of Ocean Sciences, Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, A1C 5S7, Canada
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11
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Watson KB, Lehnert SJ, Bentzen P, Kess T, Einfeldt A, Duffy S, Perriman B, Lien S, Kent M, Bradbury IR. Environmentally associated chromosomal structural variation influences fine-scale population structure of Atlantic Salmon (Salmo salar). Mol Ecol 2021; 31:1057-1075. [PMID: 34862998 DOI: 10.1111/mec.16307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/25/2021] [Accepted: 11/19/2021] [Indexed: 01/17/2023]
Abstract
Chromosomal rearrangements (e.g., inversions, fusions, and translocations) have long been associated with environmental variation in wild populations. New genomic tools provide the opportunity to examine the role of these structural variants in shaping adaptive differences within and among wild populations of non-model organisms. In Atlantic Salmon (Salmo salar), variations in chromosomal rearrangements exist across the species natural range, yet the role and importance of these structural variants in maintaining adaptive differences among wild populations remains poorly understood. We genotyped Atlantic Salmon (n = 1429) from 26 populations within a highly genetically structured region of southern Newfoundland, Canada with a 220K SNP array. Multivariate analysis, across two independent years, consistently identified variation in a structural variant (translocation between chromosomes Ssa01 and Ssa23), previously associated with evidence of trans-Atlantic secondary contact, as the dominant factor influencing population structure in the region. Redundancy analysis suggested that variation in the Ssa01/Ssa23 chromosomal translocation is strongly correlated with temperature. Our analyses suggest environmentally mediated selection acting on standing genetic variation in genomic architecture introduced through secondary contact may underpin fine-scale local adaptation in Placentia Bay, Newfoundland, Canada, a large and deep embayment, highlighting the importance of chromosomal structural variation as a driver of contemporary adaptive divergence.
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Affiliation(s)
- K Beth Watson
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.,Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, Canada
| | - Sarah J Lehnert
- Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, Canada
| | - Paul Bentzen
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Tony Kess
- Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, Canada
| | - Antony Einfeldt
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Steven Duffy
- Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, Canada
| | - Ben Perriman
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sigbjørn Lien
- Department of Animal and Aquacultural Sciences (IHA), Faculty of Life Sciences (BIOVIT), Centre for Integrative Genetics (CIGENE), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Matthew Kent
- Department of Animal and Aquacultural Sciences (IHA), Faculty of Life Sciences (BIOVIT), Centre for Integrative Genetics (CIGENE), Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Ian R Bradbury
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.,Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, Canada
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12
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Ferchaud AL, Mérot C, Normandeau E, Ragoussis J, Babin C, Djambazian H, Bérubé P, Audet C, Treble M, Walkusz W, Bernatchez L. Chromosome-level assembly reveals a putative Y-autosomal fusion in the sex determination system of the Greenland Halibut (Reinhardtius hippoglossoides). G3-GENES GENOMES GENETICS 2021; 12:6428537. [PMID: 34791178 DOI: 10.1093/g3journal/jkab376] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022]
Abstract
Despite the commercial importance of Greenland Halibut (Reinhardtius hippoglossoides), important gaps still persist in our knowledge of this species, including its reproductive biology and sex determination mechanism. Here, we combined single-molecule sequencing of long reads (Pacific Sciences) with chromatin conformation capture sequencing (Hi-C) data to assemble the first chromosome-level reference genome for this species. The high-quality assembly encompassed more than 598 Megabases (Mb) assigned to 1 594 scaffolds (scaffold N50 = 25 Mb) with 96% of its total length distributed among 24 chromosomes. Investigation of the syntenic relationship with other economically important flatfish species revealed a high conservation of synteny blocks among members of this phylogenetic clade. Sex determination analysis revealed that, similar to other teleost fishes, flatfishes also exhibit a high level of plasticity and turnover in sex-determination mechanisms. A low-coverage whole-genome sequence analysis of 198 individuals revealed that Greenland Halibut possesses a male heterogametic XY system and several putative candidate genes implied in the sex determination of this species. Our study also suggests for the first time in flatfishes that a putative Y-autosomal fusion could be associated with a reduction of recombination typical of the early steps of sex chromosome evolution.
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Affiliation(s)
- Anne-Laure Ferchaud
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, G1V 0A6, Canada
| | - Claire Mérot
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, G1V 0A6, Canada
| | - Eric Normandeau
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, G1V 0A6, Canada
| | - Jiannis Ragoussis
- McGill Genome Centre and Department for Human Genetics, McGill University, Montreal, Quebec, H3A 0G1, Canada
| | - Charles Babin
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, G1V 0A6, Canada
| | - Haig Djambazian
- McGill Genome Centre and Department for Human Genetics, McGill University, Montreal, Quebec, H3A 0G1, Canada
| | - Pierre Bérubé
- McGill Genome Centre and Department for Human Genetics, McGill University, Montreal, Quebec, H3A 0G1, Canada
| | - Céline Audet
- Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, 310 allée des Ursulines, Rimouski, QC G5L 3A1, Canada
| | - Margaret Treble
- Fisheries and Oceans Canada, Winnipeg Department, Arctic Aquatic Research Division, Freshwater Institute Winnipeg, Manitoba, R3T2N6, Canada
| | - Wocjciech Walkusz
- Fisheries and Oceans Canada, Winnipeg Department, Arctic Aquatic Research Division, Freshwater Institute Winnipeg, Manitoba, R3T2N6, Canada
| | - Louis Bernatchez
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, G1V 0A6, Canada
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13
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Hale MC, Campbell MA, McKinney GJ. A candidate chromosome inversion in Arctic charr (Salvelinus alpinus) identified by population genetic analysis techniques. G3-GENES GENOMES GENETICS 2021; 11:6329827. [PMID: 34568922 PMCID: PMC8473973 DOI: 10.1093/g3journal/jkab267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/23/2021] [Indexed: 11/13/2022]
Abstract
The "genomics era" has allowed questions to be asked about genome organization and genome architecture of non-model species at a rate not previously seen. Analyses of these genome-wide datasets have documented many examples of novel structural variants (SVs) such as chromosomal inversions, copy number variants, and chromosomal translocations, many of which have been linked to adaptation. The salmonids are a taxonomic group with abundant genome-wide datasets due to their importance in aquaculture and fisheries. However, the number of documented SVs in salmonids is surprisingly low and is most likely due to removing loci in high linkage disequilibrium when analyzing structure and gene flow. Here we re-analyze RAD-seq data from several populations of Arctic charr (Salvelinus alpinus) and document a novel ∼1.2 MB SV at the distal end of LG12. This variant contains 15 protein-coding genes connected to a wide-range of functions including cell adhesion and signal transduction. Interestingly, we studied the frequency of this polymorphism in four disjointed populations of charr-one each from Nunavut, Newfoundland, Eastern Russia, and Scotland-and found evidence of the variant only in Nunavut, Canada, suggesting the polymorphism is novel and recently evolved.
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Affiliation(s)
- Matthew C Hale
- Department of Biology, Texas Christian University, Fort Worth, TX 76129, USA
| | - Matthew A Campbell
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA.,University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Garrett J McKinney
- National Research Council Research Associateship Program, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA
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14
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Brachmann MK, Parsons K, Skúlason S, Ferguson MM. The interaction of resource use and gene flow on the phenotypic divergence of benthic and pelagic morphs of Icelandic Arctic charr ( Salvelinus alpinus). Ecol Evol 2021; 11:7315-7334. [PMID: 34188815 PMCID: PMC8216915 DOI: 10.1002/ece3.7563] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 02/09/2021] [Accepted: 03/02/2021] [Indexed: 12/11/2022] Open
Abstract
Conceptual models of adaptive divergence and ecological speciation in sympatry predict differential resource use, phenotype-environment correlations, and reduced gene flow among diverging phenotypes. While these predictions have been assessed in past studies, connections among them have rarely been assessed collectively. We examined relationships among phenotypic, ecological, and genetic variation in Arctic charr (Salvelinus alpinus) from six Icelandic localities that have undergone varying degrees of divergence into sympatric benthic and pelagic morphs. We characterized morphological variation with geometric morphometrics, tested for differential resource use between morphs using stable isotopes, and inferred the amount of gene flow from single nucleotide polymorphisms. Analysis of stable isotopic signatures indicated that sympatric morphs showed similar difference in resource use across populations, likely arising from the common utilization of niche space within each population. Carbon isotopic signature was also a significant predictor of individual variation in body shape and size, suggesting that variation in benthic and pelagic resource use is associated with phenotypic variation. The estimated percentage of hybrids between sympatric morphs varied across populations (from 0% to 15.6%) but the majority of fish had genotypes (ancestry coefficients) characteristic of pure morphs. Despite evidence of reduced gene flow between sympatric morphs, we did not detect the expected negative relationship between divergence in resource use and gene flow. Three lakes showed the expected pattern, but morphs in the fourth showed no detectable hybridization and had relatively low differences in resource use between them. This coupled with the finding that resource use and genetic differentiation had differential effects on body shape variation across populations suggests that reproductive isolation maintains phenotypic divergence between benthic and pelagic morphs when the effects of resource use are relatively low. Our ability to assess relationships between phenotype, ecology, and genetics deepens our understanding of the processes underlying adaptive divergence in sympatry.
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Affiliation(s)
| | - Kevin Parsons
- Institute of Biodiversity, Animal Health and Comparative MedicineSchool of Life ScienceUniversity of GlasgowGlasgowUK
| | - Skúli Skúlason
- Department of Aquaculture and Fish BiologyHólar UniversitySaudárkrókurIceland
- Icelandic Museum of Natural HistoryReykjavíkIceland
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15
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Venney CJ, Sutherland BJG, Beacham TD, Heath DD. Population differences in Chinook salmon ( Oncorhynchus tshawytscha) DNA methylation: Genetic drift and environmental factors. Ecol Evol 2021; 11:6846-6861. [PMID: 34141260 PMCID: PMC8207424 DOI: 10.1002/ece3.7531] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/10/2021] [Accepted: 03/17/2021] [Indexed: 12/18/2022] Open
Abstract
Local adaptation and phenotypic differences among populations have been reported in many species, though most studies focus on either neutral or adaptive genetic differentiation. With the discovery of DNA methylation, questions have arisen about its contribution to individual variation in and among natural populations. Previous studies have identified differences in methylation among populations of organisms, although most to date have been in plants and model animal species. Here we obtained eyed eggs from eight populations of Chinook salmon (Oncorhynchus tshawytscha) and assayed DNA methylation at 23 genes involved in development, immune function, stress response, and metabolism using a gene-targeted PCR-based assay for next-generation sequencing. Evidence for population differences in methylation was found at eight out of 23 gene loci after controlling for developmental timing in each individual. However, we found no correlation between freshwater environmental parameters and methylation variation among populations at those eight genes. A weak correlation was identified between pairwise DNA methylation dissimilarity among populations and pairwise F ST based on 15 microsatellite loci, indicating weak effects of genetic drift or geographic distance on methylation. The weak correlation was primarily driven by two genes, GTIIBS and Nkef. However, single-gene Mantel tests comparing methylation and pairwise F ST were not significant after Bonferroni correction. Thus, population differences in DNA methylation are more likely related to unmeasured oceanic environmental conditions, local adaptation, and/or genetic drift. DNA methylation is an additional mechanism that contributes to among population variation, with potential influences on organism phenotype, adaptive potential, and population resilience.
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Affiliation(s)
- Clare J. Venney
- Great Lakes Institute for Environmental ResearchUniversity of WindsorWindsorONCanada
| | | | - Terry D. Beacham
- Fisheries and Oceans CanadaPacific Biological StationNanaimoBCCanada
| | - Daniel D. Heath
- Great Lakes Institute for Environmental ResearchUniversity of WindsorWindsorONCanada
- Department of Integrative BiologyUniversity of WindsorWindsorONCanada
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16
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Le Moan A, Bekkevold D, Hemmer-Hansen J. Evolution at two time frames: ancient structural variants involved in post-glacial divergence of the European plaice (Pleuronectes platessa). Heredity (Edinb) 2021; 126:668-683. [PMID: 33531657 PMCID: PMC8115344 DOI: 10.1038/s41437-020-00389-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 11/05/2020] [Accepted: 11/05/2020] [Indexed: 01/30/2023] Open
Abstract
Changing environmental conditions can lead to population diversification through differential selection on standing genetic variation. Structural variant (SV) polymorphisms provide examples of ancient alleles that in time become associated with novel environmental gradients. The European plaice (Pleuronectes platessa) is a marine flatfish showing large allele-frequency differences at two putative SVs associated with environmental variation. In this study, we explored the contribution of these SVs to population structure across the North East Atlantic. We compared genome-wide population structure using sets of RAD-sequencing SNPs with the spatial structure of the SVs. We found that in contrast to the rest of the genome, the SVs were only weakly associated with an isolation-by-distance pattern. Indeed, both SVs showed important variation in haplogroup frequencies, with the same haplogroup increasing both along the salinity gradient of the Baltic Sea, and found in high frequency in the northern-range margin of the Atlantic. Phylogenetic analyses suggested that the SV alleles are much older than the age of the Baltic Sea itself. These results suggest that the SVs are older than the age of the environmental gradients with which they currently co-vary. Altogether, our results suggest that the plaice SVs were shaped by evolutionary processes occurring at two time frames, firstly following their origin, ancient spread and maintenance in the ancestral populations, and secondly related to their current association with more recently formed environmental gradients such as those found in the North Sea-Baltic Sea transition zone.
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Affiliation(s)
- Alan Le Moan
- grid.5170.30000 0001 2181 8870National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark ,grid.8761.80000 0000 9919 9582Department of Marine Sciences at Tjärnö, University of Gothenburg, Laboratorievägen 10, Strömstad, Sweden
| | - Dorte Bekkevold
- grid.5170.30000 0001 2181 8870National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - Jakob Hemmer-Hansen
- grid.5170.30000 0001 2181 8870National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
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17
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Zueva KJ, Lumme J, Veselov AE, Primmer CR, Pritchard VL. Population genomics reveals repeated signals of adaptive divergence in the Atlantic salmon of north‐eastern Europe. J Evol Biol 2020; 34:866-878. [DOI: 10.1111/jeb.13732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023]
Affiliation(s)
| | - Jaakko Lumme
- Department of Biology University of Oulu Oulu Finland
| | | | - Craig R. Primmer
- Organismal and Evolutionary Biology Research Programme University of Helsinki Helsinki Finland
- Institute of Biotechnology University of Helsinki Helsinki Finland
| | - Victoria L. Pritchard
- Organismal and Evolutionary Biology Research Programme University of Helsinki Helsinki Finland
- Rivers and Lochs Institute Inverness College University of Highlands and Islands Inverness UK
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18
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Islam SS, Wringe BF, Bradbury IR, Fleming IA. Behavioural variation among divergent European and North American farmed and wild Atlantic salmon (Salmo salar) populations. Appl Anim Behav Sci 2020. [DOI: 10.1016/j.applanim.2020.105029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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19
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Lehnert SJ, Kess T, Bentzen P, Clément M, Bradbury IR. Divergent and linked selection shape patterns of genomic differentiation between European and North American Atlantic salmon (Salmo salar). Mol Ecol 2020; 29:2160-2175. [PMID: 32432380 DOI: 10.1111/mec.15480] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 04/17/2020] [Accepted: 05/11/2020] [Indexed: 02/06/2023]
Abstract
As populations diverge many processes can shape genomic patterns of differentiation. Regions of high differentiation can arise due to divergent selection acting on selected loci, genetic hitchhiking of nearby loci, or through repeated selection against deleterious alleles (linked background selection); this divergence may then be further elevated in regions of reduced recombination. Atlantic salmon (Salmo salar) from Europe and North America diverged >600,000 years ago and despite some evidence of secondary contact, the majority of genetic data indicate substantial divergence between lineages. This deep divergence with potential gene flow provides an opportunity to investigate the role of different mechanisms that shape the genomic landscape during early speciation. Here, using 184,295 single nucleotide polymorphisms (SNPs) and 80 populations, we investigate the genomic landscape of differentiation across the Atlantic Ocean with a focus on highly differentiated regions and the processes shaping them. We found evidence of high (mean FST = 0.26) and heterogeneous genomic differentiation between continents. Genomic regions associated with high trans-Atlantic differentiation ranged in size from single loci (SNPs) within important genes to large regions (1-3 Mbp) on four chromosomes (Ssa06, Ssa13, Ssa16 and Ssa19). These regions showed signatures consistent with selection, including high linkage disequilibrium, despite no significant reduction in recombination. Genes and functional enrichment of processes associated with differentiated regions may highlight continental differences in ocean navigation and parasite resistance. Our results provide insight into potential mechanisms underlying differences between continents, and evidence of near-fixed and potentially adaptive trans-Atlantic differences concurrent with a background of high genome-wide differentiation supports subspecies designation in Atlantic salmon.
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Affiliation(s)
- Sarah J Lehnert
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, NL, Canada
| | - Tony Kess
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, NL, Canada
| | - Paul Bentzen
- Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Marie Clément
- Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute, Memorial University of Newfoundland, St. John's, NL, Canada.,Labrador Institute, Memorial University of Newfoundland, Happy Valley-Goose Bay, NL, Canada
| | - Ian R Bradbury
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, St. John's, NL, Canada.,Department of Biology, Dalhousie University, Halifax, NS, Canada
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20
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Lehnert SJ, Baillie SM, MacMillan J, Paterson IG, Buhariwalla CF, Bradbury IR, Bentzen P. Multiple decades of stocking has resulted in limited hatchery introgression in wild brook trout ( Salvelinus fontinalis) populations of Nova Scotia. Evol Appl 2020; 13:1069-1089. [PMID: 32431753 PMCID: PMC7232767 DOI: 10.1111/eva.12923] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 12/06/2019] [Accepted: 12/17/2019] [Indexed: 12/17/2022] Open
Abstract
Many populations of freshwater fishes are threatened with losses, and increasingly, the release of hatchery individuals is one strategy being implemented to support wild populations. However, stocking of hatchery individuals may pose long-term threats to wild populations, particularly if genetic interactions occur between wild and hatchery individuals. One highly prized sport fish that has been heavily stocked throughout its range is the brook trout (Salvelinus fontinalis). In Nova Scotia, Canada, hatchery brook trout have been stocked since the early 1900s, and despite continued stocking efforts, populations have suffered declines in recent decades. Before this study, the genetic structure of brook trout populations in the province was unknown; however, given the potential negative consequences associated with hatchery stocking, it is possible that hatchery programs have adversely affected the genetic integrity of wild populations. To assess the influence of hatchery supplementation on wild populations, we genotyped wild brook trout from 12 river systems and hatchery brook trout from two major hatcheries using 100 microsatellite loci. Genetic analyses of wild trout revealed extensive population genetic structure among and within river systems and significant isolation-by-distance. Hatchery stocks were genetically distinct from wild populations, and most populations showed limited to no evidence of hatchery introgression (<5% hatchery ancestry). Only a single location had a substantial number of hatchery-derived trout and was located in the only river where a local strain is used for supplementation. The amount of hatchery stocking within a watershed did not influence the level of hatchery introgression. Neutral genetic structure of wild populations was influenced by geography with some influence of climate and stocking indices. Overall, our study suggests that long-term stocking has not significantly affected the genetic integrity of wild trout populations, highlighting the variable outcomes of stocking and the need to evaluate the consequences on a case-by-case basis.
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Affiliation(s)
- Sarah J. Lehnert
- Fisheries and Oceans CanadaNorthwest Atlantic Fisheries CentreSt. John'sNLCanada
| | - Shauna M. Baillie
- Marine Gene Probe LabBiology DepartmentDalhousie UniversityHalifaxNSCanada
| | - John MacMillan
- Inland Fisheries DivisionNova Scotia Department of Fisheries and AquaculturePictouNSCanada
| | - Ian G. Paterson
- Marine Gene Probe LabBiology DepartmentDalhousie UniversityHalifaxNSCanada
| | - Colin F. Buhariwalla
- Inland Fisheries DivisionNova Scotia Department of Fisheries and AquaculturePictouNSCanada
| | - Ian R. Bradbury
- Fisheries and Oceans CanadaNorthwest Atlantic Fisheries CentreSt. John'sNLCanada
- Marine Gene Probe LabBiology DepartmentDalhousie UniversityHalifaxNSCanada
| | - Paul Bentzen
- Marine Gene Probe LabBiology DepartmentDalhousie UniversityHalifaxNSCanada
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Lehnert SJ, Kess T, Bentzen P, Kent MP, Lien S, Gilbey J, Clément M, Jeffery NW, Waples RS, Bradbury IR. Genomic signatures and correlates of widespread population declines in salmon. Nat Commun 2019; 10:2996. [PMID: 31278264 PMCID: PMC6611788 DOI: 10.1038/s41467-019-10972-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 06/11/2019] [Indexed: 12/27/2022] Open
Abstract
Global losses of biodiversity are occurring at an unprecedented rate, but causes are often unidentified. Genomic data provide an opportunity to isolate drivers of change and even predict future vulnerabilities. Atlantic salmon (Salmo salar) populations have declined range-wide, but factors responsible are poorly understood. Here, we reconstruct changes in effective population size (Ne) in recent decades for 172 range-wide populations using a linkage-based method. Across the North Atlantic, Ne has significantly declined in >60% of populations and declines are consistently temperature-associated. We identify significant polygenic associations with decline, involving genomic regions related to metabolic, developmental, and physiological processes. These regions exhibit changes in presumably adaptive diversity in declining populations consistent with contemporary shifts in body size and phenology. Genomic signatures of widespread population decline and associated risk scores allow direct and potentially predictive links between population fitness and genotype, highlighting the power of genomic resources to assess population vulnerability.
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Affiliation(s)
- S J Lehnert
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd, St. John's, Newfoundland, A1C 5X1, Canada.
| | - T Kess
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd, St. John's, Newfoundland, A1C 5X1, Canada
| | - P Bentzen
- Biology Department, Dalhousie University, 6050 University Avenue, Halifax, NS, B3H 4R2, Canada
| | - M P Kent
- Centre for Integrative Genetics (CIGENE), Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, 1430, Norway
| | - S Lien
- Centre for Integrative Genetics (CIGENE), Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, 1430, Norway
| | - J Gilbey
- Marine Scotland Science, Freshwater Fisheries Laboratory, Faskally, Pitlochry, PH16 5LB, UK
| | - M Clément
- Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute of Memorial University of Newfoundland, 155 Ridge Rd, St. John's, NL, A1C 5R3, Canada
- Labrador Institute, Memorial University of Newfoundland, 219 Hamilton River Rd, Happy Valley-Goose Bay, NL, A0P 1E0, Canada
| | - N W Jeffery
- Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Dr, Dartmouth, NS, B2Y 4A2, Canada
| | - R S Waples
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, 98112, USA
| | - I R Bradbury
- Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, 80 E White Hills Rd, St. John's, Newfoundland, A1C 5X1, Canada
- Biology Department, Dalhousie University, 6050 University Avenue, Halifax, NS, B3H 4R2, Canada
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