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Zeitler L, Parisod C, Gilbert KJ. Purging due to self-fertilization does not prevent accumulation of expansion load. PLoS Genet 2023; 19:e1010883. [PMID: 37656747 PMCID: PMC10501686 DOI: 10.1371/journal.pgen.1010883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 09/14/2023] [Accepted: 07/25/2023] [Indexed: 09/03/2023] Open
Abstract
As species expand their geographic ranges, colonizing populations face novel ecological conditions, such as new environments and limited mates, and suffer from evolutionary consequences of demographic change through bottlenecks and mutation load accumulation. Self-fertilization is often observed at species range edges and, in addition to countering the lack of mates, is hypothesized as an evolutionary advantage against load accumulation through increased homozygosity and purging. We study how selfing impacts the accumulation of genetic load during range expansion via purging and/or speed of colonization. Using simulations, we disentangle inbreeding effects due to demography versus due to selfing and find that selfers expand faster, but still accumulate load, regardless of mating system. The severity of variants contributing to this load, however, differs across mating system: higher selfing rates purge large-effect recessive variants leaving a burden of smaller-effect alleles. We compare these predictions to the mixed-mating plant Arabis alpina, using whole-genome sequences from refugial outcrossing populations versus expanded selfing populations. Empirical results indicate accumulation of expansion load along with evidence of purging in selfing populations, concordant with our simulations, suggesting that while purging is a benefit of selfing evolving during range expansions, it is not sufficient to prevent load accumulation due to range expansion.
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Affiliation(s)
- Leo Zeitler
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Christian Parisod
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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2
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Pereyra RT, Rafajlović M, De Wit P, Pinder M, Kinnby A, Töpel M, Johannesson K. Clones on the run: The genomics of a recently expanded partially clonal species. Mol Ecol 2023; 32:4209-4223. [PMID: 37199478 DOI: 10.1111/mec.16996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 05/03/2023] [Accepted: 05/05/2023] [Indexed: 05/19/2023]
Abstract
Why species that in their core areas mainly reproduce sexually become enriched with clones in marginal populations ("geographic parthenogenesis") remains unclear. Earlier hypotheses have emphasized that selection might promote clonality because it protects locally adapted genotypes. On the other hand, it also hampers recombination and adaptation to changing conditions. The aim of the present study was to investigate the early stages of range expansion in a partially clonal species and what drives an increase in cloning during such expansion. We used genome-wide sequencing to investigate the origin and evolution of large clones formed in a macroalgal species (Fucus vesiculosus) during a recent expansion into the postglacial Baltic Sea. We found low but persistent clonality in core populations, while at range margins, large dominant clonal lineages had evolved repeatedly from different sexual populations. A range expansion model showed that even when asexual recruitment is less favourable than sexual recruitment in core populations, repeated bottlenecks at the expansion front can establish a genetically eroded clonal wave that spreads ahead of a sexual wave into the new area. Genetic variation decreases by drift following repeated bottlenecks at the expansion front. This results in the emerging clones having low expected heterozygosity, which corroborated our empirical observations. We conclude that Baker's Law (clones being favoured by uniparental reproductive assurance in new areas) can play an important role during range expansion in partially clonal species, resulting in a complex spatiotemporal mosaic of clonal and sexual lineages that might persist during thousands of generations.
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Affiliation(s)
- Ricardo T Pereyra
- Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
- Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - Marina Rafajlović
- Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Pierre De Wit
- Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
- Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - Matthew Pinder
- Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Alexandra Kinnby
- Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
- Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - Mats Töpel
- Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Kerstin Johannesson
- Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
- Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
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3
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Johannesson K, Leder EH, André C, Dupont S, Eriksson SP, Harding K, Havenhand JN, Jahnke M, Jonsson PR, Kvarnemo C, Pavia H, Rafajlović M, Rödström EM, Thorndyke M, Blomberg A. Ten years of marine evolutionary biology-Challenges and achievements of a multidisciplinary research initiative. Evol Appl 2023; 16:530-541. [PMID: 36793681 PMCID: PMC9923476 DOI: 10.1111/eva.13389] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/08/2022] [Accepted: 04/21/2022] [Indexed: 11/26/2022] Open
Abstract
The Centre for Marine Evolutionary Biology (CeMEB) at the University of Gothenburg, Sweden, was established in 2008 through a 10-year research grant of 8.7 m€ to a team of senior researchers. Today, CeMEB members have contributed >500 scientific publications, 30 PhD theses and have organised 75 meetings and courses, including 18 three-day meetings and four conferences. What are the footprints of CeMEB, and how will the centre continue to play a national and international role as an important node of marine evolutionary research? In this perspective article, we first look back over the 10 years of CeMEB activities and briefly survey some of the many achievements of CeMEB. We furthermore compare the initial goals, as formulated in the grant application, with what has been achieved, and discuss challenges and milestones along the way. Finally, we bring forward some general lessons that can be learnt from a research funding of this type, and we also look ahead, discussing how CeMEB's achievements and lessons can be used as a springboard to the future of marine evolutionary biology.
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Affiliation(s)
- Kerstin Johannesson
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Erica H Leder
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden.,Natural History Museum University of Oslo Oslo Norway
| | - Carl André
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Sam Dupont
- Department of Biology and Environmental Science University of Gothenburg, Kristineberg Marine Research Station Fiskebäckskil Sweden.,International Atomic Energy Agency Principality of Monaco Monaco
| | - Susanne P Eriksson
- Department of Biology and Environmental Science University of Gothenburg, Kristineberg Marine Research Station Fiskebäckskil Sweden
| | - Karin Harding
- Department of Biology and Environmental Science University of Gothenburg Gothenburg Sweden
| | - Jonathan N Havenhand
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Marlene Jahnke
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Per R Jonsson
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Charlotta Kvarnemo
- Department of Biology and Environmental Science University of Gothenburg Gothenburg Sweden
| | - Henrik Pavia
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Marina Rafajlović
- Department of Marine Sciences University of Gothenburg Gothenburg Sweden
| | - Eva Marie Rödström
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Michael Thorndyke
- Department of Biology and Environmental Science University of Gothenburg, Kristineberg Marine Research Station Fiskebäckskil Sweden.,Department of Genomics Research in Ecology & Evolution in Nature (GREEN) Groningen Institute for Evolutionary Life Sciences (GELIFES) De Rijksuniversiteit Groningen Groningen The Netherlands
| | - Anders Blomberg
- Department of Chemistry and Molecular Biology University of Gothenburg Gothenburg Sweden
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4
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Eriksson M, Kinnby A, De Wit P, Rafajlović M. Adaptive, maladaptive, neutral, or absent plasticity: Hidden caveats of reaction norms. Evol Appl 2023; 16:486-503. [PMID: 36793703 PMCID: PMC9923493 DOI: 10.1111/eva.13482] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 08/30/2022] [Accepted: 09/06/2022] [Indexed: 11/28/2022] Open
Abstract
Adaptive phenotypic plasticity may improve the response of individuals when faced with new environmental conditions. Typically, empirical evidence for plasticity is based on phenotypic reaction norms obtained in reciprocal transplant experiments. In such experiments, individuals from their native environment are transplanted into a different environment, and a number of trait values, potentially implicated in individuals' response to the new environment, are measured. However, the interpretations of reaction norms may differ depending on the nature of the assessed traits, which may not be known beforehand. For example, for traits that contribute to local adaptation, adaptive plasticity implies nonzero slopes of reaction norms. By contrast, for traits that are correlated to fitness, high tolerance to different environments (possibly due to adaptive plasticity in traits that contribute to adaptation) may, instead, result in flat reaction norms. Here we investigate reaction norms for adaptive versus fitness-correlated traits and how they may affect the conclusions regarding the contribution of plasticity. To this end, we first simulate range expansion along an environmental gradient where plasticity evolves to different values locally and then perform reciprocal transplant experiments in silico. We show that reaction norms alone cannot inform us whether the assessed trait exhibits locally adaptive, maladaptive, neutral, or no plasticity, without any additional knowledge of the traits assessed and species' biology. We use the insights from the model to analyse and interpret empirical data from reciprocal transplant experiments involving the marine isopod Idotea balthica sampled from two geographical locations with different salinities, concluding that the low-salinity population likely has reduced adaptive plasticity relative to the high-salinity population. Overall, we conclude that, when interpreting results from reciprocal transplant experiments, it is necessary to consider whether traits assessed are locally adaptive with respect to the environmental variable accounted for in the experiments or correlated to fitness.
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Affiliation(s)
- Martin Eriksson
- Department of Marine Sciences University of Gothenburg Gothenburg Sweden.,Linnaeus Centre for Marine Evolutionary Biology University of Gothenburg Gothenburg Sweden.,Gothenburg Global Biodiversity Centre University of Gothenburg Gothenburg Sweden
| | - Alexandra Kinnby
- Linnaeus Centre for Marine Evolutionary Biology University of Gothenburg Gothenburg Sweden.,Department of Marine Sciences University of Gothenburg Strömstad-Tjärnö Sweden
| | - Pierre De Wit
- Linnaeus Centre for Marine Evolutionary Biology University of Gothenburg Gothenburg Sweden.,Department of Marine Sciences University of Gothenburg Strömstad-Tjärnö Sweden
| | - Marina Rafajlović
- Department of Marine Sciences University of Gothenburg Gothenburg Sweden.,Linnaeus Centre for Marine Evolutionary Biology University of Gothenburg Gothenburg Sweden
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5
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Almeida SC, Neiva J, Sousa F, Martins N, Cox CJ, Melo-Ferreira J, Guiry MD, Serrão EA, Pearson GA. A low-latitude species pump: Peripheral isolation, parapatric speciation and mating-system evolution converge in a marine radiation. Mol Ecol 2022; 31:4797-4817. [PMID: 35869812 DOI: 10.1111/mec.16623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 07/06/2022] [Accepted: 07/14/2022] [Indexed: 11/27/2022]
Abstract
Geologically recent radiations can shed light on speciation processes, but incomplete lineage sorting and introgressive gene flow render accurate evolutionary reconstruction and interpretation challenging. Independently evolving metapopulations of low dispersal taxa may provide an additional level of phylogeographic information, given sufficiently broad sampling and genome-wide sequencing. Evolution in the marine brown algal genus Fucus in the south-eastern North Atlantic was shaped by Quaternary climate-driven range shifts. Over this timescale, divergence and speciation occurred against a background of expansion-contraction cycles from multiple refugia, together with mating-system shifts from outcrossing (dioecy) to selfing hermaphroditism. We tested the hypothesis that peripheral isolation of range edge (dioecious) F. vesiculosus led to parapatric speciation and radiation of hermaphrodite lineages. Species tree methods using 876 single-copy nuclear genes and extensive geographic coverage produced conflicting topologies with respect to geographic clades of F. vesiculosus. All methods, however, revealed a new and early diverging hermaphrodite species, Fucus macroguiryi sp. nov. Both the multispecies coalescent and polymorphism-aware models (in contrast to concatenation) support sequential paraphyly in F. vesiculosus resulting from distinct evolutionary processes. Our results support (1) peripheral isolation of the southern F. vesiculosus clade prior to parapatric speciation and radiation of hermaphrodite lineages-a "low-latitude species pump". (2) Directional introgressive gene flow into F. vesiculosus around the present-day secondary contact zone (sympatric-allopatric boundary) between dioecious/hermaphrodite lineages as hermaphrodites expanded northwards, supported by concordance analysis and statistical tests of introgression. (3) Species boundaries in the extensive sympatric range are probably maintained by reproductive system (selfing in hermaphrodites) and reinforcement.
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Affiliation(s)
- Susana C Almeida
- Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - João Neiva
- Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - Filipe Sousa
- Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
- cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Neusa Martins
- Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - Cymon J Cox
- Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - José Melo-Ferreira
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Campus de Vairão, R. Padre Armando Quintas, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, Porto, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
| | - Michael D Guiry
- AlgaeBase, Ryan Institute, National University of Ireland, Galway, Ireland
| | - Ester A Serrão
- Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
| | - Gareth A Pearson
- Centre of Marine Sciences, Universidade do Algarve, Faro, Portugal
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Rafajlović M, Alexander JM, Butlin RK, Johannesson K. Introduction to the theme issue 'Species' ranges in the face of changing environments'. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210002. [PMID: 35184596 PMCID: PMC8859519 DOI: 10.1098/rstb.2021.0002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Understanding where, when and how species’ ranges will be modified is both a fundamental problem and essential to predicting how spatio-temporal environmental changes in abiotic and biotic factors impact biodiversity. Notably, different species may respond disparately to similar environmental changes: some species may overcome an environmental change only with difficulty or not at all, while other species may readily overcome the same change. Ranges may contract, expand or move. The drivers and consequences of this variability in species' responses remain puzzling. Importantly, changes in a species’ range creates feedbacks to the environmental conditions, populations and communities in its previous and current range, rendering population genetic, population dynamic and community processes inextricably linked. Understanding these links is critical in guiding biodiversity management and conservation efforts. This theme issue presents current thinking about the factors and mechanisms that limit and/or modify species' ranges. It also outlines different approaches to detect changes in species’ distributions, and illustrates cases of range modifications in several taxa. Overall, this theme issue highlights the urgency of understanding species' ranges but shows that we are only just beginning to disentangle the processes involved. One way forward is to unite ecology with evolutionary biology and empirical with modelling approaches. This article is part of the theme issue ‘Species’ ranges in the face of changing environments (Part II)’.
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Affiliation(s)
- Marina Rafajlović
- Department of Marine Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden.,Centre for Marine Evolutionary Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Jake M Alexander
- Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Roger K Butlin
- Centre for Marine Evolutionary Biology, University of Gothenburg, 405 30 Gothenburg, Sweden.,Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK.,Department of Marine Sciences, University of Gothenburg, Tjärnö Marine Laboratory, 452 96 Strömstad, Sweden
| | - Kerstin Johannesson
- Centre for Marine Evolutionary Biology, University of Gothenburg, 405 30 Gothenburg, Sweden.,Department of Marine Sciences, University of Gothenburg, Tjärnö Marine Laboratory, 452 96 Strömstad, Sweden
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7
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Bridle J, Hoffmann A. Understanding the biology of species' ranges: when and how does evolution change the rules of ecological engagement? Philos Trans R Soc Lond B Biol Sci 2022; 377:20210027. [PMID: 35184590 PMCID: PMC8859517 DOI: 10.1098/rstb.2021.0027] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Understanding processes that limit species' ranges has been a core issue in ecology and evolutionary biology for many decades, and has become increasingly important given the need to predict the responses of biological communities to rapid environmental change. However, we still have a poor understanding of evolution at range limits and its capacity to change the ecological 'rules of engagement' that define these communities, as well as the time frame over which this occurs. Here we link papers in the current volume to some key concepts involved in the interactions between evolutionary and ecological processes at species' margins. In particular, we separate hypotheses about species' margins that focus on hard evolutionary limits, which determine how genotypes interact with their environment, from those concerned with soft evolutionary limits, which determine where and when local adaptation can persist in space and time. We show how theoretical models and empirical studies highlight conditions under which gene flow can expand local limits as well as contain them. In doing so, we emphasize the complex interplay between selection, demography and population structure throughout a species' geographical and ecological range that determines its persistence in biological communities. However, despite some impressively detailed studies on range limits, particularly in invertebrates and plants, few generalizations have emerged that can predict evolutionary responses at ecological margins. We outline some directions for future work such as considering the impact of structural genetic variants and metapopulation structure on limits, and the interaction between range limits and the evolution of mating systems and non-random dispersal. This article is part of the theme issue 'Species' ranges in the face of changing environments (Part II)'.
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Affiliation(s)
- Jon Bridle
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Ary Hoffmann
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Australia
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Eriksson M, Rafajlović M. The role of phenotypic plasticity in the establishment of range margins. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210012. [PMID: 35067091 PMCID: PMC8784930 DOI: 10.1098/rstb.2021.0012] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 11/16/2021] [Indexed: 12/15/2022] Open
Abstract
It has been argued that adaptive phenotypic plasticity may facilitate range expansions over spatially and temporally variable environments. However, plasticity may induce fitness costs. This may hinder the evolution of plasticity. Earlier modelling studies examined the role of plasticity during range expansions of populations with fixed genetic variance. However, genetic variance evolves in natural populations. This may critically alter model outcomes. We ask: how does the capacity for plasticity in populations with evolving genetic variance alter range margins that populations without the capacity for plasticity are expected to attain? We answered this question using computer simulations and analytical approximations. We found a critical plasticity cost above which the capacity for plasticity has no impact on the expected range of the population. Below the critical cost, by contrast, plasticity facilitates range expansion, extending the range in comparison to that expected for populations without plasticity. We further found that populations may evolve plasticity to buffer temporal environmental fluctuations, but only when the plasticity cost is below the critical cost. Thus, the cost of plasticity is a key factor involved in range expansions of populations with the potential to express plastic response in the adaptive trait. This article is part of the theme issue 'Species' ranges in the face of changing environments (part I)'.
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Affiliation(s)
- Martin Eriksson
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, University of Gothenburg, Gothenburg, Sweden
| | - Marina Rafajlović
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
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