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Liu A, Geraldes A, Taylor EB. Historical and contemporary processes driving the origin and structure of an admixed population within a contact zone between subspecies of a north temperate diadromous fish. Mol Ecol 2024; 33:e17459. [PMID: 38994921 DOI: 10.1111/mec.17459] [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: 11/30/2023] [Revised: 04/23/2024] [Accepted: 04/30/2024] [Indexed: 07/13/2024]
Abstract
Hybridization between divergent lineages can result in losses of distinct evolutionary taxa. Alternatively, hybridization can lead to increased genetic variability that may fuel local adaptation and the generation of novel traits and/or taxa. Here, we examined single-nucleotide polymorphisms generated using genotyping-by-sequencing in a population of Dolly Varden char (Pisces: Salmonidae) that is highly admixed within a contact zone between two subspecies (Salvelinus malma malma, Northern Dolly Varden [NDV] and S. m. lordi, Southern Dolly Varden [SDV]) in southwestern Alaska to assess the spatial distribution of hybrids and to test hypotheses on the origin of the admixed population. Ancestry analysis revealed that this admixed population is composed of advanced generation hybrids between NDV and SDV or advanced backcrosses to SDV; no F1 hybrids were detected. Coalescent-based demographic modelling supported the origin of this population about 55,000 years ago by secondary contact between NDV and SDV with low levels of contemporary gene flow. Ancestry in NDV and SDV varies within the watershed and ancestry in NDV was positively associated with distance upstream from the sea, contingent on habitat-type sampled, and negatively associated with the number of migrations that individual fish made to the sea. Our results suggest that divergence between subspecies over hundreds of thousands of years may not be associated with significant reproductive isolation, but that elevated diversity owing to hybridization may have contributed to adaptive divergence in habitat use and life history.
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Affiliation(s)
- Amy Liu
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Armando Geraldes
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric B Taylor
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Beaty Biodiversity Museum, University of British Columbia, Vancouver, British Columbia, Canada
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2
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Salisbury SJ, Ruzzante DE. Genetic Causes and Consequences of Sympatric Morph Divergence in Salmonidae: A Search for Mechanisms. Annu Rev Anim Biosci 2021; 10:81-106. [PMID: 34758272 DOI: 10.1146/annurev-animal-051021-080709] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Repeatedly and recently evolved sympatric morphs exhibiting consistent phenotypic differences provide natural experimental replicates of speciation. Because such morphs are observed frequently in Salmonidae, this clade provides a rare opportunity to uncover the genomic mechanisms underpinning speciation. Such insight is also critical for conserving salmonid diversity, the loss of which could have significant ecological and economic consequences. Our review suggests that genetic differentiation among sympatric morphs is largely nonparallel apart from a few key genes that may be critical for consistently driving morph differentiation. We discuss alternative levels of parallelism likely underlying consistent morph differentiation and identify several factors that may temper this incipient speciation between sympatric morphs, including glacial history and contemporary selective pressures. Our synthesis demonstrates that salmonids are useful for studying speciation and poses additional research questions to be answered by future study of this family. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 10 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- S J Salisbury
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada; ,
| | - D E Ruzzante
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada; ,
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3
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Wang D, Gao L, Tian H, Dong W, Duan X, Liu S, Chen D. Population genetics and sympatric divergence of the freshwater gudgeon, Gobiobotia filifer, in the Yangtze River inferred from mitochondrial DNA. Ecol Evol 2020; 10:50-58. [PMID: 31993113 PMCID: PMC6972953 DOI: 10.1002/ece3.5746] [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: 11/14/2018] [Revised: 09/09/2019] [Accepted: 09/16/2019] [Indexed: 12/02/2022] Open
Abstract
The ecosystem and Pleistocene glaciations play important roles in population demography. The freshwater gudgeon, Gobiobotia filifer, is an endemic benthic fish in the Yangtze River and is a good model for ecological and evolutionary studies. This study aimed to decode the population structure of G. filifer in the Yangtze River and reveal whether divergence occurred before or after population radiation. A total of 292 specimens from eight locations in the upper and middle reaches of the Yangtze River were collected from 2014 to 2016 and analyzed via mitochondrial DNA Cyt b gene sequencing. A moderately high level of genetic diversity was found without structures among the population. However, phylogenetic and network topology showed two distinct haplotype groups, and each group contained a similar proportion of individuals from all sampled sites. This suggested the existence of two genetically divergent source populations in G. filifer. We deduced that a secondary contact of distinct glacial refugia was the main factor creating sympatric populations of G. filifer, and climate improvement promoted population expansion and colonization.
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Affiliation(s)
- Dengqiang Wang
- Yangtze River Fisheries Research InstituteChinese Academy of Fishery ScienceWuhanChina
| | - Lei Gao
- Yangtze River Fisheries Research InstituteChinese Academy of Fishery ScienceWuhanChina
| | - Huiwu Tian
- Yangtze River Fisheries Research InstituteChinese Academy of Fishery ScienceWuhanChina
| | - Weiwei Dong
- Yangtze River Fisheries Research InstituteChinese Academy of Fishery ScienceWuhanChina
- School of Life ScienceSouthwest UniversityChongqingChina
| | - Xinbin Duan
- Yangtze River Fisheries Research InstituteChinese Academy of Fishery ScienceWuhanChina
| | - Shaoping Liu
- Yangtze River Fisheries Research InstituteChinese Academy of Fishery ScienceWuhanChina
| | - Daqing Chen
- Yangtze River Fisheries Research InstituteChinese Academy of Fishery ScienceWuhanChina
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4
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Skúlason S, Parsons KJ, Svanbäck R, Räsänen K, Ferguson MM, Adams CE, Amundsen P, Bartels P, Bean CW, Boughman JW, Englund G, Guðbrandsson J, Hooker OE, Hudson AG, Kahilainen KK, Knudsen R, Kristjánsson BK, Leblanc CA, Jónsson Z, Öhlund G, Smith C, Snorrason SS. A way forward with eco evo devo: an extended theory of resource polymorphism with postglacial fishes as model systems. Biol Rev Camb Philos Soc 2019; 94:1786-1808. [PMID: 31215138 PMCID: PMC6852119 DOI: 10.1111/brv.12534] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/12/2019] [Accepted: 05/20/2019] [Indexed: 12/16/2022]
Abstract
A major goal of evolutionary science is to understand how biological diversity is generated and altered. Despite considerable advances, we still have limited insight into how phenotypic variation arises and is sorted by natural selection. Here we argue that an integrated view, which merges ecology, evolution and developmental biology (eco evo devo) on an equal footing, is needed to understand the multifaceted role of the environment in simultaneously determining the development of the phenotype and the nature of the selective environment, and how organisms in turn affect the environment through eco evo and eco devo feedbacks. To illustrate the usefulness of an integrated eco evo devo perspective, we connect it with the theory of resource polymorphism (i.e. the phenotypic and genetic diversification that occurs in response to variation in available resources). In so doing, we highlight fishes from recently glaciated freshwater systems as exceptionally well-suited model systems for testing predictions of an eco evo devo framework in studies of diversification. Studies on these fishes show that intraspecific diversity can evolve rapidly, and that this process is jointly facilitated by (i) the availability of diverse environments promoting divergent natural selection; (ii) dynamic developmental processes sensitive to environmental and genetic signals; and (iii) eco evo and eco devo feedbacks influencing the selective and developmental environments of the phenotype. We highlight empirical examples and present a conceptual model for the generation of resource polymorphism - emphasizing eco evo devo, and identify current gaps in knowledge.
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Affiliation(s)
- Skúli Skúlason
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókur, 551Iceland
- Icelandic Museum of Natural History, Brynjólfsgata 5ReykjavíkIS‐107Iceland
| | - Kevin J. Parsons
- Institute of Biodiversity, Animal Health & Comparative MedicineUniversity of GlasgowGlasgow, G12 8QQU.K.
| | - Richard Svanbäck
- Animal Ecology, Department of Ecology and Genetics, Science for Life LaboratoryUppsala University, Norbyvägen 18DUppsala, SE‐752 36Sweden
| | - Katja Räsänen
- Department of Aquatic EcologyEAWAG, Swiss Federal Institute of Aquatic Science and Technology, and Institute of Integrative Biology, ETH‐Zurich, Ueberlandstrasse 133CH‐8600DübendorfSwitzerland
| | - Moira M. Ferguson
- Department of Integrative BiologyUniversity of GuelphGuelph, Ontario N1G 2W1Canada
| | - Colin E. Adams
- Scottish Centre for Ecology and the Natural Environment, IBAHCMUniversity of GlasgowGlasgow G12 8QQU.K.
| | - Per‐Arne Amundsen
- Freshwater Ecology Group, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and EconomicsUniversity of TromsöTromsö, N‐9037Norway
| | - Pia Bartels
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Colin W. Bean
- Scottish Natural Heritage, Caspian House, Mariner Court, Clydebank Business ParkClydebank, G81 2NRU.K.
| | - Janette W. Boughman
- Department of Integrative BiologyMichigan State UniversityEast Lansing, MI 48824U.S.A.
| | - Göran Englund
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Jóhannes Guðbrandsson
- Institute of Life and Environmental SciencesUniversity of IcelandReykjavik, 101Iceland
| | | | - Alan G. Hudson
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Kimmo K. Kahilainen
- Inland Norway University of Applied Sciences, Department of Forestry and Wildlife Management, Campus Evenstad, Anne Evenstadvei 80Koppang, NO‐2480Norway
| | - Rune Knudsen
- Freshwater Ecology Group, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and EconomicsUniversity of TromsöTromsö, N‐9037Norway
| | | | - Camille A‐L. Leblanc
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókur, 551Iceland
| | - Zophonías Jónsson
- Institute of Life and Environmental SciencesUniversity of IcelandReykjavik, 101Iceland
| | - Gunnar Öhlund
- Department of Ecology and Environmental ScienceUmeå UniversityUmeå, SE‐90187Sweden
| | - Carl Smith
- School of BiologyUniversity of St Andrews, St. AndrewsFife, KY16 9AJU.K.
| | - Sigurður S. Snorrason
- Institute of Life and Environmental SciencesUniversity of IcelandReykjavik, 101Iceland
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5
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Abstract
Abstract
Conservation planning of threatened taxa relies upon accurate data on systematics, ecological traits and suitable habitats. The genus Gazella includes taxa with distinct morphologies and ecological traits, but close phylogenetic relationships. The North African Gazella cuvieri and Gazella leptoceros loderi share morphological and physiological characters but the former is darker and found in mountain areas, while the latter is lighter and associated with sand dunes. Here we aim to assess the genetic distinctiveness of these taxa, to characterize their ecological niches and to identify potential occurrence areas, by analysing 327 samples across North-West Africa. Phylogenetic analyses based on mitochondrial (CYTB) and five nuclear gene fragments (KCAS, LAC, SPTBN1, PRKCI and THYR) show that both taxa comprise a single monophyletic group. However, ecological niche-based modelling suggests that populations of these taxa occupy distinct geographic areas and specific environments. Predicted areas of sympatry were restricted, as a consequence of local sharp transitions in climatic traits. The lack of genetic differentiation between these taxa suggests they should be lumped into G. cuvieri, while ecological and morphological differences indicate they correspond to distinct ecotypes. Conservation planning of G. cuvieri should consider the preservation of both mountain and lowland ecotypes to maintain the overall adaptive potential of the species. This integrative approach provides valuable insights in identifying evolutionary units and should be extended to other gazelles.
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Andersson A, Jansson E, Wennerström L, Chiriboga F, Arnyasi M, Kent MP, Ryman N, Laikre L. Complex genetic diversity patterns of cryptic, sympatric brown trout (Salmo trutta) populations in tiny mountain lakes. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-0972-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Johnson SD, Moré M, Amorim FW, Haber WA, Frankie GW, Stanley DA, Coccuci AA, Raguso RA. The long and the short of it: a global analysis of hawkmoth pollination niches and interaction networks. Funct Ecol 2016; 31:101-115. [PMID: 28344378 DOI: 10.1111/1365-2435.12753] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. Proboscis length has been proposed as a key dimension of plant pollination niches, but this niche space has not previously been explored at regional and global scales for any pollination system. Hawkmoths are ideal organisms for exploring pollinator niches as they are important pollinators in most of the biodiverse regions of the earth and vary greatly in proboscis length, with some species having the longest proboscides of all insects. 2. Using datasets for nine biogeographical regions spanning the Old and New World, we ask whether it is possible to identify distinct hawkmoth pollination niches based on the frequency distribution of proboscis length, and whether these niches are reflected in the depths of flowers that are pollinated by hawkmoths. We also investigate the levels of specialization in hawkmoth pollination systems at the regional and community level using data from interaction network studies. 3. We found that most regional hawkmoth assemblages have bimodal or multimodal distributions of proboscis length, and that these are matched by similar distributions of floral tube lengths. Hawkmoths, particularly those with longer proboscides, are polyphagous and at the network level show foraging specialization equivalent to or less than that of bees and hummingbirds. In the case of plants, shorter-tubed flowers are usually visited by numerous hawkmoth species, while those that are longer-tubed tend to exclude shorter-proboscid hawkmoths and thus become ecologically specialized on longer-proboscid hawkmoth species. Longer-tubed flowers tend to have greater nectar rewards and this promotes short-term constancy by long-proboscid hawkmoths. 4. Our results show that pollinator proboscis length is a key niche axis for plants and can account for patterns of evolution in functional traits such as floral tube length and nectar volume. We also highlight a paradoxical trend for nectar resource niche breadth to increase according to proboscis length of pollinators, while pollinator niche breadth decreases according to the tube length of flowers.
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Affiliation(s)
- Steven D Johnson
- School of Life Sciences, University of KwaZulu-Natal, P Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
| | - Marcela Moré
- Laboratorio de Biologıa Floral, Instituto Multidisciplinario de Biologıa Vegetal (CONICET-UNCba), CC 495, CP 5000, Cordoba, Argentina
| | - Felipe W Amorim
- Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, São Paulo, Brazil
| | | | - Gordon W Frankie
- Department of Environmental Science, Policy, & Management, UC Berkeley, 130 Mulford Hall #3114, Berkeley, CA 94720, USA
| | - Dara A Stanley
- School of Life Sciences, University of KwaZulu-Natal, P Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
| | - Andrea A Coccuci
- Laboratorio de Biologıa Floral, Instituto Multidisciplinario de Biologıa Vegetal (CONICET-UNCba), CC 495, CP 5000, Cordoba, Argentina
| | - Robert A Raguso
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
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8
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Adams CE, Bean CW, Dodd JA, Down A, Etheridge EC, Gowans ARD, Hooker O, Knudsen R, Lyle AA, Winfield IJ, Præbel K. Inter and intra-population phenotypic and genotypic structuring in the European whitefish Coregonus lavaretus, a rare freshwater fish in Scotland. JOURNAL OF FISH BIOLOGY 2016; 88:580-594. [PMID: 26748995 DOI: 10.1111/jfb.12855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 11/02/2015] [Indexed: 06/05/2023]
Abstract
This study revealed between-lake genetic structuring between Coregonus lavaretus collected from the only two native populations of this species in Scotland, U.K. (Lochs Eck and Lomond) evidenced by the existence of private alleles (12 in Lomond and four in Eck) and significant genetic differentiation (FST = 0·056) across 10 microsatellite markers. Juvenile C. lavaretus originating from eggs collected from the two lakes and reared in a common-garden experiment showed clear phenotypic differences in trophic morphology (i.e. head and body shape) between these populations indicating that these characteristics were, at least partly, inherited. Microsatellite analysis of adults collected from different geographic regions within Loch Lomond revealed detectable and statistically significant but relatively weak genetic structuring (FST = 0·001-0·024) and evidence of private alleles related to the basin structure of the lake. Within-lake genetic divergence patterns suggest three possibilities for this observed pattern: (1) differential selection pressures causing divergence into separate gene pools, (2) a collapse of two formerly divergent gene pools and (3) a stable state maintained by balancing selection forces resulting from spatial variation in selection and lake heterogeneity. Small estimates of effective population sizes for the populations in both lakes suggest that the capacity of both populations to adapt to future environmental change may be limited.
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Affiliation(s)
- C E Adams
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - C W Bean
- Scottish Natural Heritage, Caspian House, Clydebank Business Park, Clydebank, Glasgow G81 2NR, U.K
| | - J A Dodd
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - A Down
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - E C Etheridge
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - A R D Gowans
- Environment Agency, Ghyll Mount, Gillan Way, Penrith 40 Business Park, Penrith, Cumbria CA11 9BP, U.K
| | - O Hooker
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - R Knudsen
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
| | - A A Lyle
- Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Rowardennan, Glasgow G63 0AW, U.K
| | - I J Winfield
- Lake Ecosystems Group, Centre for Ecology & Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP, U.K
| | - K Præbel
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9037 Tromsø, Norway
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9
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Ford AGP, Dasmahapatra KK, Rüber L, Gharbi K, Cezard T, Day JJ. High levels of interspecific gene flow in an endemic cichlid fish adaptive radiation from an extreme lake environment. Mol Ecol 2015; 24:3421-40. [PMID: 25997156 PMCID: PMC4973668 DOI: 10.1111/mec.13247] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/13/2015] [Accepted: 05/13/2015] [Indexed: 12/30/2022]
Abstract
Studying recent adaptive radiations in isolated insular systems avoids complicating causal events and thus may offer clearer insight into mechanisms generating biological diversity. Here, we investigate evolutionary relationships and genomic differentiation within the recent radiation of Alcolapia cichlid fish that exhibit extensive phenotypic diversification, and which are confined to the extreme soda lakes Magadi and Natron in East Africa. We generated an extensive RAD data set of 96 individuals from multiple sampling sites and found evidence for genetic admixture between species within Lake Natron, with the highest levels of admixture between sympatric populations of the most recently diverged species. Despite considerable environmental separation, populations within Lake Natron do not exhibit isolation by distance, indicating panmixia within the lake, although individuals within lineages clustered by population in phylogenomic analysis. Our results indicate exceptionally low genetic differentiation across the radiation despite considerable phenotypic trophic variation, supporting previous findings from smaller data sets; however, with the increased power of densely sampled SNPs, we identify genomic peaks of differentiation (FST outliers) between Alcolapia species. While evidence of ongoing gene flow and interspecies hybridization in certain populations suggests that Alcolapia species are incompletely reproductively isolated, the identification of outlier SNPs under diversifying selection indicates the radiation is undergoing adaptive divergence.
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Affiliation(s)
- Antonia G P Ford
- Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK
| | | | - Lukas Rüber
- Naturhistorisches Museum der Burgergemeinde Bern, Bernastrasse 15, Bern, 3005, Switzerland
| | - Karim Gharbi
- Edinburgh Genomics, Ashworth Laboratories, The University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Timothee Cezard
- Edinburgh Genomics, Ashworth Laboratories, The University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Julia J Day
- Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK
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10
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Evolution and origin of sympatric shallow-water morphotypes of Lake Trout, Salvelinus namaycush, in Canada's Great Bear Lake. Heredity (Edinb) 2014; 114:94-106. [PMID: 25204304 DOI: 10.1038/hdy.2014.74] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 06/24/2014] [Accepted: 07/14/2014] [Indexed: 11/09/2022] Open
Abstract
Range expansion in north-temperate fishes subsequent to the retreat of the Wisconsinan glaciers has resulted in the rapid colonization of previously unexploited, heterogeneous habitats and, in many situations, secondary contact among conspecific lineages that were once previously isolated. Such ecological opportunity coupled with reduced competition likely promoted morphological and genetic differentiation within and among post-glacial fish populations. Discrete morphological forms existing in sympatry, for example, have now been described in many species, yet few studies have directly assessed the association between morphological and genetic variation. Morphotypes of Lake Trout, Salvelinus namaycush, are found in several large-lake systems including Great Bear Lake (GBL), Northwest Territories, Canada, where several shallow-water forms are known. Here, we assess microsatellite and mitochondrial DNA variation among four morphotypes of Lake Trout from the five distinct arms of GBL, and also from locations outside of this system to evaluate several hypotheses concerning the evolution of morphological variation in this species. Our data indicate that morphotypes of Lake Trout from GBL are genetically differentiated from one another, yet the morphotypes are still genetically more similar to one another compared with populations from outside of this system. Furthermore, our data suggest that Lake Trout colonized GBL following dispersal from a single glacial refugium (the Mississippian) and support an intra-lake model of divergence. Overall, our study provides insights into the origins of morphological and genetic variation in post-glacial populations of fishes and provides benchmarks important for monitoring Lake Trout biodiversity in a region thought to be disproportionately susceptible to impacts from climate change.
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11
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Bond MH, Crane PA, Larson WA, Quinn TP. Is isolation by adaptation driving genetic divergence among proximate Dolly Varden char populations? Ecol Evol 2014; 4:2515-32. [PMID: 25360283 PMCID: PMC4203295 DOI: 10.1002/ece3.1113] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 04/16/2014] [Accepted: 04/23/2014] [Indexed: 01/26/2023] Open
Abstract
Numerous studies of population genetics in salmonids and other anadromous fishes have revealed that population structure is generally organized into geographic hierarchies (isolation by distance), but significant structure can exist in proximate populations due to varying selective pressures (isolation by adaptation). In Chignik Lakes, Alaska, anadromous Dolly Varden char (Salvelinus malma) spawn in nearly all accessible streams throughout the watershed, including those draining directly to an estuary, Chignik Lagoon, into larger rivers, and into lakes. Collections of Dolly Varden fry from 13 streams throughout the system revealed low levels of population structure among streams emptying into freshwater. However, much stronger genetic differentiation was detected between streams emptying into freshwater and streams flowing directly into estuarine environments. This fine-scale reproductive isolation without any physical barriers to migration is likely driven by differences in selection pressures across freshwater and estuarine environments. Estuary tributaries had fewer larger, older juveniles, suggesting an alternative life history of smolting and migration to the marine environment at a much smaller size than occurs in the other populations. Therefore, genetic data were consistent with a scenario where isolation by adaptation occurs between populations of Dolly Varden in the study system, and ecological data suggest that this isolation may partially be a result of a novel Dolly Varden life history of seawater tolerance at a smaller size than previously recognized.
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Affiliation(s)
- Morgan H Bond
- School of Aquatic and Fishery Sciences, University of Washington Box 355020, Seattle, Washington, 98195
| | - Penelope A Crane
- Conservation Genetics Laboratory, U.S. Fish and Wildlife Service 1011 East Tudor Road, Anchorage, Alaska, 99503
| | - Wesley A Larson
- School of Aquatic and Fishery Sciences, University of Washington Box 355020, Seattle, Washington, 98195
| | - Tom P Quinn
- School of Aquatic and Fishery Sciences, University of Washington Box 355020, Seattle, Washington, 98195
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12
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Franchini P, Fruciano C, Spreitzer ML, Jones JC, Elmer KR, Henning F, Meyer A. Genomic architecture of ecologically divergent body shape in a pair of sympatric crater lake cichlid fishes. Mol Ecol 2013; 23:1828-45. [PMID: 24237636 DOI: 10.1111/mec.12590] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 10/18/2013] [Accepted: 10/28/2013] [Indexed: 12/26/2022]
Abstract
Determining the genetic bases of adaptations and their roles in speciation is a prominent issue in evolutionary biology. Cichlid fish species flocks are a prime example of recent rapid radiations, often associated with adaptive phenotypic divergence from a common ancestor within a short period of time. In several radiations of freshwater fishes, divergence in ecomorphological traits - including body shape, colour, lips and jaws - is thought to underlie their ecological differentiation, specialization and, ultimately, speciation. The Midas cichlid species complex (Amphilophus spp.) of Nicaragua provides one of the few known examples of sympatric speciation where species have rapidly evolved different but parallel morphologies in young crater lakes. This study identified significant QTL for body shape using SNPs generated via ddRAD sequencing and geometric morphometric analyses of a cross between two ecologically and morphologically divergent, sympatric cichlid species endemic to crater Lake Apoyo: an elongated limnetic species (Amphilophus zaliosus) and a high-bodied benthic species (Amphilophus astorquii). A total of 453 genome-wide informative SNPs were identified in 240 F2 hybrids. These markers were used to construct a genetic map in which 25 linkage groups were resolved. Seventy-two segregating SNPs were linked to 11 QTL. By annotating the two most highly supported QTL-linked genomic regions, genes that might contribute to divergence in body shape along the benthic-limnetic axis in Midas cichlid sympatric adaptive radiations were identified. These results suggest that few genomic regions of large effect contribute to early stage divergence in Midas cichlids.
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Affiliation(s)
- Paolo Franchini
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätstraße 10, 78457, Konstanz, Germany
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Siwertsson A, Knudsen R, Adams CE, Præbel K, Amundsen PA. Parallel and non-parallel morphological divergence among foraging specialists in European whitefish (Coregonus lavaretus). Ecol Evol 2013; 3:1590-602. [PMID: 23789070 PMCID: PMC3686194 DOI: 10.1002/ece3.562] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 11/19/2022] Open
Abstract
Parallel phenotypic evolution occurs when independent populations evolve similar traits in response to similar selective regimes. However, populations inhabiting similar environments also frequently show some phenotypic differences that result from non-parallel evolution. In this study, we quantified the relative importance of parallel evolution to similar foraging regimes and non-parallel lake-specific effects on morphological variation in European whitefish (Coregonus lavaretus). We found evidence for both lake-specific morphological characteristics and parallel morphological divergence between whitefish specializing in feeding on profundal and littoral resources in three separate lakes. Foraging specialists expressed similar phenotypes in different lakes in both overall body shape and selected measured morphological traits. The morphology of the two whitefish specialists resembled that predicted from other fish species, supporting the conclusion of an adaptive significance of the observed morphological characteristics. Our results indicate that divergent natural selection resulting from foraging specialization is driving and/or maintaining the observed parallel morphological divergence. Whitefish in this study may represent an early stage of divergence towards the evolution of specialized morphs.
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Affiliation(s)
- Anna Siwertsson
- Department of Arctic and Marine Biology, University of Tromsø N-9037 Tromsø, Norway
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