Marte Sodeland

• Saha, Atal; Jorde, Per Erik; Sodeland, Marte; Albretsen, Jon; Korslund, Lars & Knutsen, Halvor (2025). Genomic population structure and local adaptation in the emerging commercially exploited Littorina littorea. ICES Journal of Marine Science. ISSN 1054-3139. 82(7). doi: 10.1093/icesjms/fsaf119. Fulltekst i vitenarkiv Vis sammendrag

  To address food deficit, stakeholders continuously diversify food systems by exploiting new commercially viable species. However, the absence of sustainable management measures often conflicts with global biodiversity policies. In light of this challenge, understanding genetic diversity and the geographic scale of population connectivity is essential. We employ ddRAD sequencing in Littorina littorea, a low-trophic, emerging commercial species, to investigate its genetic population structure in Norwegian coastal waters. From an initial detection of over two million SNPs (single nucleotide polymorphisms), 60 831 loci were retained for downstream genomic analyses in 189 individuals sampled across 17 coastal sites. Our results revealed significant isolation-by-distance across the study area, likely reflecting genetic divergence between populations along the west and southern coasts of Norway. While the overall genetic structure appears to be primarily shaped by genetic drift, our genome scan analyses provided evidence for selection acting on specific loci. We identified 39 SNPs potentially under selection, of which 16 overlapped with genes encoding proteins involved in transmembrane transport, metabolic processes, and pathogenesis-related functions. We found no evidence supporting the presence of chromosomal inversions. Oceanographic modelling suggests a likely link between observed genetic divergence and the prevailing ocean current in the region. Our findings demonstrate the adaptive potential of distinct populations to varying environmental conditions and highlight the importance of preserving their full genetic diversity to ensure long-term resilience and sustainability.

• Martinossi-Allibert, Ivain; Ratikainen, Irja Ida; Albretsen, Jon; Eknes, Eirin Jetmundsen; Ellingsen, Ingrid Helene & Estalella, Claudia Aparicio [Vis alle 13 forfattere av denne artikkelen] (2025). Meeting the challenge of latitude: a climatic gradient shapes the reproductive strategy of a nest-brooding marine fish. Marine Ecology Progress Series. ISSN 0171-8630. 767, s. 101–120. doi: 10.3354/meps14895. Fulltekst i vitenarkiv Vis sammendrag

  High-latitude environments represent climate-related challenges, imposing a limit on species distributions. By elucidating how marine species adjust their reproductive strategy to cope with climatic variation, we can better predict the resilience of populations to environmental change. We addressed this question with a large-scale field study of a marine fish with a central role in the northeast Atlantic coastal ecosystem: the two-spotted goby Pomatoschistus flavescens . We developed a multi-faceted approach to examine how the species’ reproductive strategy and life history change along a climatic gradient. Six populations were surveyed along a gradient of 10° latitude, nearly reaching the northern limit of the species’ range, combining environmental, physiological, phenotypic and demographic data with a genomics investigation of population connectivity. Northern fish experienced colder environments for growth and reproduction than their southern counterparts, occurred at lower adult density and had lower body condition. At high latitudes, a different life history strategy emerged, whereby adults reproduced as 2 yr olds rather than 1 yr olds. Genomics analyses unveiled a clear genetic structure, with a break in connectivity between Skagerrak and the Norwegian coast further north, consistent with findings in other marine species. However, our genomic analyses did not provide clear evidence of adaptation to ecological variables, leaving open questions about the roles of adaptation and plasticity in latitudinal shifts in reproductive strategy. The study highlights the complex life history adaptations to high latitudes in a marine species with high gene flow and underscores the importance of sea temperature on fish reproductive strategy.

• Saha, Atal; Jorde, Per Erik; Sodeland, Marte; Korslund, Lars & Knutsen, Halvor (2025). Pelagic Larval Duration and Isolation by Distance in Coastal Species. Evolutionary Applications. 18(12). doi: 10.1111/eva.70187. Fulltekst i vitenarkiv Vis sammendrag

  Dispersal among populations is crucial both for demographic stability and for the evolutionary potential of species. In marine organisms, dispersal has been shown to be prevalent during pelagic early life stages. Consequently, pelagic larval duration (PLD) has been proposed as an important driver of gene flow in marine species and is influencing genetic differentiation among populations. Despite this prediction, empirical studies have often failed to find the expected correlation between PLD and genetic metrics of gene flow. This could mean either that PLD is a poor predictor of gene flow or that differences in methodology, oceanography or sampling design across studies obscure the underlying mechanisms of gene flow. In the present study, we address these issues by using a consistent sampling design for 10 coastal species with previously published genetic data (ddRAD and microsatellites), and that differ in PLD. We investigate gene flow using an isolation-by-distance (IBD) model with pairwise FST-estimates regressed against distances measured along the prevailing coastal ocean current in the study region. We find a significant (p < 0.05) correlation between species' PLD and IBD slopes, with a moderately strong correlation (r2 > 0.5), These findings support the notion of PLD as a key factor determining dispersal and gene flow among populations of coastal species. Our findings reiterate genetics as a useful tool for inferring population dispersal in marine organisms when potentially confounding factors are eliminated by adopting a consistent sampling design.

• Hagen, Ingerid Julie; Skaala, Øystein; Quintela, Maria; Dahle, Geir; Fiske, Peder & Foldvik, Anders [Vis alle 13 forfattere av denne artikkelen] (2025). The genetic structure of sea trout (<i>Salmo trutta</i> L.) in Norway. ICES Journal of Marine Science. ISSN 1054-3139. 82(9). doi: 10.1093/icesjms/fsaf151. Fulltekst i vitenarkiv Vis sammendrag

  Sea trout is the anadromous form of brown trout (Salmo trutta) and is culturally, economically, and ecologically important across its native distribution. Here, we describe the genetic structure of sea trout caught in 105 rivers from the 2600 km long Norwegian coast using &gt;3000 individuals genotyped for 93 SNPs. Our results indicated that most of the study populations are genetically different from each other with a mean pairwise FST of 0.067. While most genetic variation was found within the different populations (93.2%), around 4.5% variation was found between rivers within the different fjord systems and neighbor joining analysis generally grouped together populations from the same fjord or geographic region. Isolation by distance (IBD) for the 105 populations was significant (r2 = 0.21), but the same analysis on three smaller spatial scales revealed different patterns: significant IBD in the Hardangerfjord, moderate IBD in the Sognefjord, and no IBD for the 28 most northern populations, altogether suggesting that there is not a simple relationship between geographic distance and genetic isolation. This documentation of sea trout intra-specific biodiversity must be considered in conservation of the intra-specific diversity of sea trout, including prioritizing habitat restoration, stocks included in genebank, and protection from negative impacts from aquaculture.

• Norderhaug, Kjell Magnus; Knutsen, Halvor; Filbee-Dexter, Karen; Sodeland, Marte; Jorde, Per Erik & Wernberg, Thomas [Vis alle 8 forfattere av denne artikkelen] (2024). The International Union for Conservation of Nature Red List does not account for intraspecific diversity. ICES Journal of Marine Science. ISSN 1054-3139. 81(5), s. 815–822. doi: 10.1093/icesjms/fsae039. Fulltekst i vitenarkiv Vis sammendrag

  The International Union for Conservation of Nature (IUCN) Red List identifies threatened and endangered species and is a key instrument in global biodiversity conservation efforts. Our understanding of the structure and value of genetic biodiversity below the species level is rapidly increasing. Nonetheless, the IUCN assessment criteria overlook genetic variation within species. Here, we address this blind spot and discuss the principles of species conservation status classification relative to intraspecific biodiversity. We focus on coastal species, which thrive in heterogeneous environments known to drive genetic differentiation. The focal example species, Atlantic cod and sugar kelp, have contrasting life histories, are ecologically and economically important constituents of the coastal ecosystem, and are currently not classified as threatened in Norway and Canada. We expose important variation in population structure, the presence of ecotypes and genetic-environment covariation, as well as loss of ecotypes that threatens the conservation of these species. Because the genetic makeup of species directly influences their resilience, omitting this information from conservation status assessments can result in loss of adaptive capacity to future stressors, such as climate change. Consequently, recognizing and preserving intraspecific variation emerges as vital for species’ abilities to adapt to and survive in future ocean conditions.

• Gustafsson, Malin; Strand, Åsa; Laugen, Ane Timenes; Albretsen, Jon; André, Carl & Broström, Göran [Vis alle 13 forfattere av denne artikkelen] (2024). Unlocking the secret life of blue mussels: Exploring connectivity in the Skagerrak through biophysical modeling and population genomics. Evolutionary Applications. 17(5), s. 1–18. doi: 10.1111/eva.13704. Fulltekst i vitenarkiv Vis sammendrag

  Knowledge of functional dispersal barriers in the marine environment can be used to inform a wide variety of management actions, such as marine spatial planning, restoration efforts, fisheries regulations, and invasive species management. Locations and causes of dispersal barriers can be studied through various methods, including movement tracking, biophysical modeling, demographic models, and genetics. Combining methods illustrating potential dispersal, such as biophysical modeling, with realized dispersal through, e.g., genetic connectivity estimates, provides particularly useful information for teasing apart potential causes of observed barriers. In this study, we focus on blue mussels (Mytilus edulis) in the Skagerrak—a marginal sea connected to the North Sea in Northern Europe—and combine biophysical models of larval dispersal with genomic data to infer locations and causes of dispersal barriers in the area. Results from both methods agree; patterns of ocean currents are a major structuring factor in the area. We find a complex pattern of source-sink dynamics with several dispersal barriers and show that some areas can be isolated despite an overall high dispersal capability. Finally, we translate our finding into management advice that can be used to sustainably manage this ecologically and economically important species in the future.

• Bekkevold, Dorte; Knutsen, Halvor; Hemmer-Hansen, Jakob; Sodeland, Marte; Höjesjö, Johan & Bleeker, Katinka [Vis alle 9 forfattere av denne artikkelen] (2024). Genetic monitoring uncovers long-distance marine feeding coupled with strong spatial segregation in sea trout (Salmo trutta L.) consistent at annual and decadal time scales. ICES Journal of Marine Science. ISSN 1054-3139. 81(8), s. 1655–1668. doi: 10.1093/icesjms/fsae114. Fulltekst i vitenarkiv Vis sammendrag

  Genetic data have greatly increased means to understand fish marine migration behaviours at large spatial scale within a quantitative framework. The anadromous sea trout is a prized target of recreational fishery and an important ecosystem component in freshwater and marine coastal habitats in large parts of temperate northern Europe. Nonetheless, little is known about population distributions while feeding at sea. To reconcile notions about feeding migrations being predominantly locally restricted or not, we used SNP data for 3465 trout representing >100 rivers to identify population origins of 903 coastally feeding fish captured throughout the North Sea-Baltic Sea transition area. Across areas, coastal collections generally showed marked stock-mixing and overall 70:30% native:non-native fish with seasonal variation corresponding with spawning run timing. Data revealed strong spatial feeding segregation between trout from the Scandinavian Peninsula and the European continent. This is surprising given the short distances between areas, but is in alignment with strong genetic differentiation between populations in these areas. Estimation of stock complexity of coastal feeding aggregations showed no spatial trend through the North Sea-Baltic Sea transition area otherwise characterized by strong environmental clines. Analyses of scale samples collected in the 1950s indicate that stock-mixing was consistent over almost 70 years.

• Koeck, Barbara; Olsen, Esben Moland; Závorka, Libor; Crespel, Amélie; Freitas, Carla & Enberg, Katja [Vis alle 11 forfattere av denne artikkelen] (2024). Conservation benefits of marine reserves depend on knowledge integration of genotypic and phenotypic diversity. Biological Conservation. ISSN 0006-3207. 299. doi: 10.1016/j.biocon.2024.110831. Fulltekst i vitenarkiv Vis sammendrag

  Conserving intraspecific trait variation is vital for maintaining the viability of species. It ensures a species to adapt to warming and increasingly stochastic environments, and to recover following extreme events. Here we investigate the selective effects of spatial management on intraspecific genetic and phenotypic variation of two sympatric but genetically distinct Atlantic cod ecotypes in a Norwegian fjord. We found that phenotypic differences between sympatric cod genotypes were mainly driven by morphological and metabolic traits. Offshore cod had higher metabolic maintenance costs at cool temperatures but lower aerobic capacity at warm acclimation than coastal ecotypes, indicative of thermal constraint of aerobic physiological processes beyond metabolic maintenance. Offshore cod also had larger and thicker peduncles and better body condition. We found that protection benefits from the no-take zone (NTZ) of the Tvedestrand marine protected area were independent of individual space-use size, but instead resulted from ecotype-specific differences in habitat occupation. Results specifically show that the current delimitations of the NTZ do not cover habitats occupied by the coastal and highly resident cod ecotype which shows greater metabolic thermal tolerance but is considered to already be in a depleted state. Our study exemplifies why protecting intraspecific diversity is directly relevant for management implementations aimed at reducing the impact of further selection pressures such as ongoing environmental change. Careful investigation of intraspecific diversity and integration of such knowledge to fisheries management and design of protected areas may prevent unwanted additional selective pressures and contribute to offer broad protection to genotypes and phenotypes.

• Sodeland, Marte; Jentoft, Sissel; Jorde, Per Erik; Mattingsdal, Morten; Albretsen, Jon & Kleiven, Alf Ring [Vis alle 12 forfattere av denne artikkelen] (2022). Stabilizing selection on Atlantic cod supergenes through a millennium of extensive exploitation. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 119(8). doi: 10.1073/pnas.2114904119. Fulltekst i vitenarkiv Vis sammendrag

  Life on Earth has been characterized by recurring cycles of ecological stasis and disruption, relating biological eras to geological and climatic transitions through the history of our planet. Due to the increasing degree of ecological abruption caused by human influences many advocate that we now have entered the geological era of the Anthropocene, or “the age of man.” Considering the ongoing mass extinction and ecosystem reshuffling observed worldwide, a better understanding of the drivers of ecological stasis will be a requisite for identifying routes of intervention and mitigation. Ecosystem stability may rely on one or a few keystone species, and the loss of such species could potentially have detrimental effects. The Atlantic cod (Gadus morhua) has historically been highly abundant and is considered a keystone species in ecosystems of the northern Atlantic Ocean. Collapses of cod stocks have been observed on both sides of the Atlantic and reported to have detrimental effects that include vast ecosystem reshuffling. By whole-genome resequencing we demonstrate that stabilizing selection maintains three extensive “supergenes” in Atlantic cod, linking these genes to species persistence and ecological stasis. Genomic inference of historic effective population sizes shows continued declines for cod in the North Sea–Skagerrak–Kattegat system through the past millennia, consistent with an early onset of the marine Anthropocene through industrialization and commercialization of fisheries throughout the medieval period.

• Henriksson, Simon; Pereyra, Ricardo; Sodeland, Marte; Ortega-Martinez, Olga; Knutsen, Halvor & Wennhage, Håkan [Vis alle 7 forfattere av denne artikkelen] (2022). Mixed origin of juvenile Atlantic cod (Gadus morhua) along the Swedish west coast. ICES Journal of Marine Science. ISSN 1054-3139. 80(1), s. 145–157. doi: 10.1093/icesjms/fsac220. Fulltekst i vitenarkiv Vis sammendrag

  Cryptic population structure in exploited fishes poses a major challenge for fisheries management. In Atlantic cod, sympatric ecotypes are well-known, for instance off the coast of northern Norway. Recently, two sympatric cod ecotypes have also been documented in the Skagerrak and Kattegat, where adult cod has declined dramatically. One ecotype has an apparent offshore origin and displays a more migratory lifestyle than the other, which is generally resident at the coast throughout its life. To investigate their relative abundances along the Swedish west coast, juvenile cod were collected at high spatial resolution along the coast and genetically assigned to ecotypes. The results reveal large proportions of the coastal ecotype in the southern Kattegat, Öresund, and inshore Swedish Skagerrak, whereas the offshore ecotype dominates in offshore areas. A regression model comparison suggests that differences in bottom depth, rather than distance from the open sea, explain the heterogeneous spatial distribution of the two ecotypes. In addition, the two ecotypes display genetic differences suggesting adaptation to different environments. The results underline that successful fisheries management requires identification and consideration of locally adapted sympatric ecotypes.

• Knutsen, Halvor; Catarino, Diana Sofia de Oliveira; Rogers, Lauren; Sodeland, Marte; Mattingsdal, Morten & Jahnke, Marlene [Vis alle 15 forfattere av denne artikkelen] (2022). Combining population genomics with demographic analyses highlights habitat patchiness and larval dispersal as determinants of connectivity in coastal fish species. Molecular Ecology. ISSN 0962-1083. 31(9), s. 2562–2577. doi: 10.1111/mec.16415. Fulltekst i vitenarkiv Vis sammendrag

  Gene flow shapes spatial genetic structure and the potential for local adaptation. Among marine animals with nonmigratory adults, the presence or absence of a pelagic larval stage is thought to be a key determinant in shaping gene flow and the genetic structure of populations. In addition, the spatial distribution of suitable habitats is expected to influence the distribution of biological populations and their connectivity patterns. We used whole genome sequencing to study demographic history and reduced representation (double-digest restriction associated DNA) sequencing data to analyse spatial genetic structure in broadnosed pipefish (Syngnathus typhle). Its main habitat is eelgrass beds, which are patchily distributed along the study area in southern Norway. Demographic connectivity among populations was inferred from long-term (~30-year) population counts that uncovered a rapid decline in spatial correlations in abundance with distance as short as ~2 km. These findings were contrasted with data for two other fish species that have a pelagic larval stage (corkwing wrasse, Symphodus melops; black goby, Gobius niger). For these latter species, we found wider spatial scales of connectivity and weaker genetic isolation-by-distance patterns, except where both species experienced a strong barrier to gene flow, seemingly due to lack of suitable habitat. Our findings verify expectations that a fragmented habitat and absence of a pelagic larval stage promote genetic structure, while presence of a pelagic larvae stage increases demographic connectivity and gene flow, except perhaps over extensive habitat gaps.

• Deininger, Anne; Martin, Angela Helen; Pardo, Juan; Berg, Paul Ragnar; Bhardwaj, Jyotirmoy & Catarino, Diana Sofia de Oliveira [Vis alle 15 forfattere av denne artikkelen] (2021). Coastal Research Seen Through an Early Career Lens—A Perspective on Barriers to Interdisciplinarity in Norway. Frontiers in Marine Science. 8. doi: 10.3389/fmars.2021.634999. Fulltekst i vitenarkiv Vis sammendrag

  The value of interdisciplinarity for solving complex coastal problems is widely recognized. Many early career researchers (ECRs) therefore actively seek this type of collaboration through choice or necessity, for professional development or project funding. However, establishing and conducting interdisciplinary research collaborations as an ECR has many challenges. Here, we identify these challenges through the lens of ECRs working in different disciplines on a common ecosystem, the Norwegian Skagerrak coast. The most densely populated coastline in Norway, the Skagerrak coast, is experiencing a multitude of anthropogenic stressors including fishing, aquaculture, eutrophication, climate change, land runoff, development, and invasive species. The Skagerrak coastline has also been the focus of environmental science research for decades, much of which aims to inform management of these stressors. The region provides a fantastic opportunity for interdisciplinary collaboration, both within and beyond the environmental sciences. This perspective article identifies the barriers ECRs in Norway face in establishing interdisciplinary and collaborative research to inform management of coastal ecosystems, along with their root causes. We believe our discussion will be of broad interest to all research institutions who employ or educate ECRs (in Norway and worldwide), and to those who develop funding mechanisms for ECRs and interdisciplinary research.

• Synnes, Ann-Elin; Huserbråten, Mats Brockstedt Olsen; Knutsen, Halvor; Jorde, Per Erik; Sodeland, Marte & Moland, Even (2021). Local recruitment of Atlantic cod and putative source spawning areas in a coastal seascape. ICES Journal of Marine Science. ISSN 1054-3139. 78(10), s. 3767–3779. doi: 10.1093/icesjms/fsab226. Fulltekst i vitenarkiv Vis sammendrag

  Increased knowledge on connectivity is crucial to our understanding of the population dynamics, genetic structure, and biogeography of many coastal species. In coastal marine populations, the main factor for structuring is thought to be the degree of isolation and confinement, limiting genetic exchange between populations. However, many offshore populations use the coastal areas as nursery grounds, but venture back to natal spawning grounds as adults. Therefore, increased knowledge on the connectivity between coastal and offshore populations is crucial to ensure correct assessment of coastal living resources. Here, we combine genetic assignment data of Atlantic cod recruits sampled in 2017 and 2018 (as 0- and 1-group cod, respectively) in outer Oslofjord (eastern Skagerrak) with a biophysical model for the Skagerrak region over the time period from spawning to settlement in 2017. We located the most probable spawning locations of Atlantic cod recruits by “back-tracking” larval drift trajectories and found putative source areas on both sides of the outer Oslofjord, as well as potential upstream sources in the North Sea and Kattegat. Findings are discussed with regards to suitable management strategies and potential for restoration of coastal cod populations.

• Helgeland, Hanna; Sodeland, Marte; Zoric, Nina; Torgersen, Jacob Seilø; Grammes, Fabian & Lintig, Johannes von [Vis alle 10 forfattere av denne artikkelen] (2019). Genomic and functional gene studies suggest a key role of beta-carotene oxygenase 1 like (bco1l) gene in salmon flesh color. Scientific Reports. 9. doi: 10.1038/s41598-019-56438-3. Fulltekst i vitenarkiv Vis sammendrag

  Red coloration of muscle tissue (flesh) is a unique trait in several salmonid genera, including Atlantic salmon. The color results from dietary carotenoids deposited in the flesh, whereas the color intensity is affected both by diet and genetic components. Herein we report on a genome-wide association study (GWAS) to identify genetic variation underlying this trait. Two SNPs on ssa26 showed strong associations to the flesh color in salmon. Two genes known to be involved in carotenoid metabolism were located in this QTL- region: beta-carotene oxygenase 1 (bco1) and beta-carotene oxygenase 1 like (bco1l). To determine whether flesh color variation is caused by one, or both, of these genes, functional studies were carried out including mRNA and protein expression in fish with red and pale flesh color. The catalytic abilities of these two genes were also tested with different carotenoids. Our results suggest bco1l to be the most likely gene to explain the flesh color variation observed in this population.

• Bekkevold, Dorte; Höjesjö, Johan; Nielsen, Einar Eg; Aldvén, David; Als, Thomas Damm & Sodeland, Marte [Vis alle 9 forfattere av denne artikkelen] (2019). Northern European Salmo trutta (L.) populations are genetically divergent across geographical regions and environmental gradients. Evolutionary Applications. doi: 10.1111/eva.12877. Fulltekst i vitenarkiv Vis sammendrag

  The salmonid fish Brown trout is iconic as a model for the application of conservation genetics to understand and manage local interspecific variation. However, there is still scant information about relationships between local and large‐scale population structure, and to what extent geographical and environmental variables are associated with barriers to gene flow. We used information from 3,782 mapped SNPs developed for the present study and conducted outlier tests and gene–environment association (GEA) analyses in order to examine drivers of population structure. Analyses comprised >2,600 fish from 72 riverine populations spanning a central part of the species' distribution in northern Europe. We report hitherto unidentified genetic breaks in population structure, indicating strong barriers to gene flow. GEA loci were widely spread across genomic regions and showed correlations with climatic, abiotic and geographical parameters. In some cases, individual loci showed consistent GEA across the geographical regions Britain, Europe and Scandinavia. In other cases, correlations were observed only within a sub‐set of regions, suggesting that locusspecific variation was associated with local processes. A paired‐population sampling design allowed us to evaluate sampling effects on detection of outlier loci and GEA. Two widely applied methods for outlier detection (pcadapt and bayescan) showed low overlap in loci identified as statistical outliers across sub‐sets of data. Two GEA analytical approaches (LFMM and RDA) showed good correspondence concerning loci associated with specific variables, but LFMM identified five times more statistically significant associations than RDA. Our results emphasize the importance of carefully considering the statistical methods applied for the hypotheses being tested in outlier analysis. Sampling design may have lower impact on results if the objective is to identify GEA loci and their population distribution. Our study provides new insights into trout populations, and results have direct management implications in serving as a tool for identification of conservation units.

• Mattingsdal, Morten; Jorde, Per Erik; Knutsen, Halvor; Jentoft, Sissel; Stenseth, Nils Christian & Sodeland, Marte [Vis alle 10 forfattere av denne artikkelen] (2019). Demographic history has shaped the strongly differentiated corkwing wrasse populations in Northern Europe. Molecular Ecology. ISSN 0962-1083. 29(1), s. 1–12. doi: 10.1111/mec.15310. Fulltekst i vitenarkiv Vis sammendrag

  Understanding the biological processes involved in genetic differentiation and divergence between populations within species is a pivotal aim in evolutionary biology. One particular phenomenon that requires clarification is the maintenance of genetic barriers despite the high potential for gene flow in the marine environment. Such patterns have been attributed to limited dispersal or local adaptation, and to a lesser extent to the demographic history of the species. The corkwing wrasse (<i>Symphodus melops</i>) is an example of a marine fish species where regions of particular strong divergence are observed. One such genetic break occurred at a surprisingly small spatial scale (<i>F</i>_ST ~0.1), over a short coastline (<60 km) in the North Sea‐Skagerrak transition area in southwestern Norway. Here, we investigate the observed divergence and purported reproductive isolation using genome resequencing. Our results suggest that historical events during the post‐glacial recolonization route can explain the present population structure of the corkwing wrasse in the northeast Atlantic. While the divergence across the break is strong, we detected ongoing gene flow between populations over the break suggesting recent contact or negative selection against hybrids. Moreover, we found few outlier loci and no clear genomic regions potentially being under selection. We concluded that neutral processes and random genetic drift e.g., due to founder events during colonization have shaped the population structure in this species in Northern Europe. Our findings underline the need to take into account the demographic process in studies of divergence processes.

• Jorde, Per Erik; Synnes, Ann-Elin; Espeland, Sigurd Heiberg; Sodeland, Marte & Knutsen, Halvor (2018). Can we rely on selected genetic markers for population identification? Evidence from coastal Atlantic cod. Ecology and Evolution. 8(24), s. 12547–12558. doi: 10.1002/ece3.4648. Fulltekst i vitenarkiv Vis sammendrag

  The use of genetic markers under putative selection in population studies carries the potential for erroneous identification of populations and misassignment of individuals to population of origin. Selected markers are nevertheless attractive, especially in marine organisms that are characterized by weak population structure at neutral loci. Highly fecund species may tolerate the cost of strong selective mortality during early life stages, potentially leading to a shift in offspring genotypes away from the parental proportions. In Atlantic cod, recent genetic studies have uncovered different genotype clusters apparently representing phenotypically cryptic populations that coexist in coastal waters. Here, we tested if a high‐graded SNP panel specifically designed to classify individual cod to population of origin may be unreliable because of natural selection acting on the SNPs or their linked background. Temporal samples of cod were collected from two fjords, starting at the earliest life stage (pelagic eggs) and carried on until late autumn (bottom‐settled juveniles), covering the period during summer of high natural mortality. Despite the potential for selective mortality during the study period, we found no evidence for selection, as both cod types occurred throughout the season, already in the earliest egg samples, and there was no evidence for a shift during the season in the proportions of one or the other type. We conclude that high‐graded marker panels under putative natural selection represent a valid and useful tool for identifying biological population structure in this highly fecund species and presumably in others.

• Jorde, Per Erik; Kleiven, Alf Ring; Sodeland, Marte; Olsen, Esben Moland; Ferter, Keno & Jentoft, Sissel [Vis alle 7 forfattere av denne artikkelen] (2018). Who is fishing on what stock: Population-of-origin of individual cod (Gadus morhua) in commercial and recreational fisheries. ICES Journal of Marine Science. ISSN 1054-3139. 75(6), s. 2153–2162. doi: 10.1093/icesjms/fsy080. Fulltekst i vitenarkiv
• Knutsen, Halvor; Jorde, Per Erik; Hutchings, Jeffrey; Hemmer-Hansen, Jakob; Grønkjær, Peter & Jørgensen, Kris-Emil Mose [Vis alle 10 forfattere av denne artikkelen] (2018). Stable coexistence of genetically divergent Atlantic cod ecotypes at multiple spatial scales. Evolutionary Applications. 11(9), s. 1527–1539. doi: 10.1111/eva.12640. Fulltekst i vitenarkiv Vis sammendrag

  Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding of local population structure and adaptation. Identifying the underlying mechanisms for such coexistence can yield new insight into adaptive evolution, diversification and the potential for organisms to adapt and persist in response to a changing environment. Recent studies have documented cryptic, sympatric populations of Atlantic cod (Gadus morhua) in coastal areas. We analysed genetic origin of 6,483 individual cod sampled annually over 14 years from 125 locations along the Norwegian Skagerrak coast and document stable coexistence of two genetically divergent Atlantic cod ecotypes throughout the study area and study period. A “fjord” ecotype dominated in numbers deep inside fjords while a “North Sea” ecotype was the only type found in offshore North Sea. Both ecotypes coexisted in similar proportions throughout coastal habitats at all spatial scales. The size‐at‐age of the North Sea ecotype on average exceeded that of the fjord ecotype by 20% in length and 80% in weight across all habitats. Different growth and size among individuals of the two types might be one of several ecologically significant variables that allow for stable coexistence of closely related populations within the same habitat. Management plans, biodiversity initiatives and other mitigation strategies that do not account for the mixture of species ecotypes are unlikely to meet objectives related to the sustainability of fish and fisheries.

• Olsen, Hanne Gro; Knutsen, Tim Martin; Kohler, Achim; Svendsen, Morten; Gidskehaug, Lars Halvor & Grove, Harald [Vis alle 12 forfattere av denne artikkelen] (2017). Genome-wide association mapping for milk fat composition and fine mapping of a QTL for de novo synthesis of milk fatty acids on bovine chromosome 13. Genetics Selection Evolution. ISSN 0999-193X. 49:20, s. 1–13. doi: 10.1186/s12711-017-0294-5. Fulltekst i vitenarkiv Vis sammendrag

  Background Bovine milk is widely regarded as a nutritious food source for humans, although the effects of individual fatty acids on human health is a subject of debate. Based on the assumption that genomic selection offers potential to improve milk fat composition, there is strong interest to understand more about the genetic factors that influence the biosynthesis of bovine milk and the molecular mechanisms that regulate milk fat synthesis and secretion. For this reason, the work reported here aimed at identifying genetic variants that affect milk fatty acid composition in Norwegian Red cattle. Milk fatty acid composition was predicted from the nation-wide recording scheme using Fourier transform infrared spectroscopy data and applied to estimate heritabilities for 36 individual and combined fatty acid traits. The recordings were used to generate daughter yield deviations that were first applied in a genome-wide association (GWAS) study with 17,343 markers to identify quantitative trait loci (QTL) affecting fatty acid composition, and next on high-density and sequence-level datasets to fine-map the most significant QTL on BTA13 (BTA for Bos taurus chromosome). Results The initial GWAS revealed 200 significant associations, with the strongest signals on BTA1, 13 and 15. The BTA13 QTL highlighted a strong functional candidate gene for de novo synthesis of short- and medium-chained saturated fatty acids; acyl-CoA synthetase short-chain family member 2. However, subsequent fine-mapping using single nucleotide polymorphisms (SNPs) from a high-density chip and variants detected by resequencing showed that the effect was more likely caused by a second nearby gene; nuclear receptor coactivator 6 (NCOA6). These findings were confirmed with results from haplotype studies. NCOA6 is a nuclear receptor that interacts with transcription factors such as PPARγ, which is a major regulator of bovine milk fat synthesis. Conclusions An initial GWAS revealed a highly significant QTL for de novo-synthesized fatty acids on BTA13 and was followed by fine-mapping of the QTL within NCOA6. The most significant SNPs were either synonymous or situated in introns; more research is needed to uncover the underlying causal DNA variation(s).

• Sodeland, Marte; Jorde, Per Erik; Lien, Sigbjørn; Jentoft, Sissel; Berg, Paul Ragnar & Grove, Harald [Vis alle 10 forfattere av denne artikkelen] (2016). "Islands of divergence" in the Atlantic cod genome represent polymorphic chromosomal rearrangements. Genome Biology and Evolution (GBE). 8(4), s. 1012–1022. doi: 10.1093/gbe/evw057. Fulltekst i vitenarkiv Vis sammendrag

  In several species genetic differentiation across environmental gradients or between geographically separate populations has been reported to center at “genomic islands of divergence,” resulting in heterogeneous differentiation patterns across genomes. Here, genomic regions of elevated divergence were observed on three chromosomes of the highly mobile fish Atlantic cod (Gadus morhua) within geographically fine-scaled coastal areas. The “genomic islands” extended at least 5, 9.5, and 13 megabases on linkage groups 2, 7, and 12, respectively, and coincided with large blocks of linkage disequilibrium. For each of these three chromosomes, pairs of segregating, highly divergent alleles were identified, with little or no gene exchange between them. These patterns of recombination and divergence mirror genomic signatures previously described for large polymorphic inversions, which have been shown to repress recombination across extensive chromosomal segments. The lack of genetic exchange permits divergence between noninverted and inverted chromosomes in spite of gene flow. For the rearrangements on linkage groups 2 and 12, allelic frequency shifts between coastal and oceanic environments suggest a role in ecological adaptation, in agreement with recently reported associations between molecular variation within these genomic regions and temperature, oxygen, and salinity levels. Elevated genetic differentiation in these genomic regions has previously been described on both sides of the Atlantic Ocean, and we therefore suggest that these polymorphisms are involved in adaptive divergence across the species distributional range.

• Berg, Paul Ragnar; Star, Bastiaan; Pampoulie, Christophe; Sodeland, Marte; Barth, Julia Maria Isis & Knutsen, Halvor [Vis alle 8 forfattere av denne artikkelen] (2016). Three chromosomal rearrangements promote genomic divergence between migratory and stationary ecotypes of Atlantic cod. Scientific Reports. 6, s. 1–12. doi: 10.1038/srep23246. Fulltekst i vitenarkiv Vis sammendrag

  Identification of genome-wide patterns of divergence provides insight on how genomes are influenced by selection and can reveal the potential for local adaptation in spatially structured populations. In Atlantic cod – historically a major marine resource – Northeast-Arctic- and Norwegian coastal cod are recognized by fundamental differences in migratory and non-migratory behavior, respectively. However, the genomic architecture underlying such behavioral ecotypes is unclear. Here, we have analyzed more than 8.000 polymorphic SNPs distributed throughout all 23 linkage groups and show that loci putatively under selection are localized within three distinct genomic regions, each of several megabases long, covering approximately 4% of the Atlantic cod genome. These regions likely represent genomic inversions. The frequency of these distinct regions differ markedly between the ecotypes, spawning in the vicinity of each other, which contrasts with the low level of divergence in the rest of the genome. The observed patterns strongly suggest that these chromosomal rearrangements are instrumental in local adaptation and separation of Atlantic cod populations, leaving footprints of large genomic regions under selection. Our findings demonstrate the power of using genomic information in further understanding the population dynamics and defining management units in one of the world’s most economically important marine resources.

• Olsen, Hanne Gro; Knutsen, Tim; Lewandowska-Sabat, Anna; Grove, Harald; Nome, Torfinn & Svendsen, Morten [Vis alle 15 forfattere av denne artikkelen] (2016). Fine mapping of a QTL on bovine chromosome 6 using imputed full sequence data suggests a key role for the group-specific component (GC) gene in clinical mastitis and milk production. Genetics Selection Evolution. ISSN 0999-193X. 48(1). doi: 10.1186/s12711-016-0257-2. Fulltekst i vitenarkiv
• Sodeland, Marte; Gaarder, Mari; Moen, Thomas; Thomassen, Magny S.; Kjøglum, Sissel & Kent, Matthew Peter [Vis alle 7 forfattere av denne artikkelen] (2013). Genome-wide association testing reveals quantitative trait loci for fillet texture and fat content in Atlantic salmon. Aquaculture. ISSN 0044-8486. 408-409, s. 169–174. doi: 10.1016/j.aquaculture.2013.05.029. Fulltekst i vitenarkiv
• Sodeland, Marte; Kent, Matthew Peter; Hayes, Ben J.; Grove, Harald & Lien, Sigbjørn (2011). Recent and historical recombination in the admixed Norwegian Red cattle breed. BMC Genomics. 12. doi: 10.1186/1471-2164-12-33. Fulltekst i vitenarkiv
• Sodeland, Marte; Grove, Harald; Kent, Matthew Peter; Taylor, Simon; Svendsen, Morten & Hayes, Ben J. [Vis alle 7 forfattere av denne artikkelen] (2011). Molecular characterization of a long range haplotype affecting protein yield and mastitis susceptibility in Norwegian Red cattle. BMC Genetics. 12. doi: 10.1186/1471-2156-12-70. Fulltekst i vitenarkiv
• Sodeland, Marte; Kent, Matthew Peter; Olsen, Hanne Gro; Opsal, Monica Aasland; Svendsen, Morten & Sehested, Erling [Vis alle 8 forfattere av denne artikkelen] (2011). Quantitative trait loci for clinical mastitis on chromosomes 2, 6, 14 and 20 in Norwegian Red cattle. Animal Genetics. ISSN 0268-9146. 42(5), s. 457–465. doi: 10.1111/j.1365-2052.2010.02165.x. Fulltekst i vitenarkiv
• Liu, Yue; Qin, Xiang; Song, Xing-Zhi Henry; Jiang, Huaiyang; Shen, Yufeng & Durbin, K. James [Vis alle 16 forfattere av denne artikkelen] (2009). Bos taurus genome assembly. BMC Genomics. 10. doi: 10.1186/1471-2164-10-180. Fulltekst i vitenarkiv Vis sammendrag

  Conclusion: The biological analysis of this bovine genome assembly is being published, and the sequence data is available to support future bovine research.

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• Lien, Anne; Nygård, Malene Østreng; Laugen, Ane Timenes; Lie, Asbjørn; Slettan, Audun & Johansen, Beate Strøm [Vis alle 33 forfattere av denne artikkelen] (2023). Utbygging vil ødelegge for biologisk mangfold på campus Gimlemoen. NB! 34 forfattere totalt. s. 19–19. Fulltekst i vitenarkiv
• Gonzalez, Enrique Blanco; Jentoft, Sissel; Hansen, Michael Møller; Knutsen, Halvor; Sodeland, Marte & Mattingsdal, Morten [Vis alle 9 forfattere av denne artikkelen] (2018). Understanding adaptation in translocating wrasses. Fulltekst i vitenarkiv
• Sodeland, Marte; Moen, Thomas; Kent, Matthew Peter; Kjøglum, Sissel; Bahuaud, Diane & Gaarder, Mari [Vis alle 8 forfattere av denne artikkelen] (2012). Genome-wide association studies for fat content and fillet firmness in Atlantic salmon. Fulltekst i vitenarkiv
• Lewandowska-Sabat, Anna; Boman, Guro M.; Sodeland, Marte; Heringstad, Bjørg; Storset, Anne & Lien, SIgbjørn [Vis alle 7 forfattere av denne artikkelen] (2011). Bovine macrophages and mastitis: In vitro gene response to Staphylococcus aureus exposure. Fulltekst i vitenarkiv
• Lewandowska-Sabat, Anna; Boman, Guro M; Sodeland, Marte; Heringstad, Bjørg; Storset, Anne & Lien, Sigbjørn [Vis alle 7 forfattere av denne artikkelen] (2011). Bovine macrophages and mastitis: in vitro gene response to Staphylococcus aureus exposure. Fulltekst i vitenarkiv
• Fuglebakk, Edvin; Thorsen, Anders; Mellerud, Ida Kristin; Sodeland, Marte & Sannæs, Hanne (2024). Genetisk analyse av skreitoktets eggsurvey 2022. Havforskningsinstituttet. Fulltekst i vitenarkiv Vis sammendrag

  Vi har bestemt artssammensetning i eggprøver fra skreitoktets eggsurvey i 2022 med genetisk analyse. Formålet har vært å kvalitetssikre den mikroskopiske artsbestemmelsen som inngår i den faste skreitoktprotokollen. Vi har særlig vært interessert i forvekslingsfaren mellom torsk og hyse, ettersom disse ikke lar seg skille ved mikroskopi. Vi fant en lavere mengde hyseegg enn det som var ventet ut i fra fangster av gytende hyse og nær samtidige tokt i nær overlappende område. Noen få håvtrekk hadde også store mengder egg som ikke lot seg sikkert bestemme genetisk. Det klare flertall av håvtrekk var imidlertid genetisk bestemt med få usikre egg, og vi fant i hovedsak svært godt samsvar mellom artsbestemmelse gjort ved hjelp av henholdsvis mikroskop og genetikk.

• Lien, Anne; Nygård, Malene Østreng; Bjørnestøl, Katharina Reionn; Gjelsvik, Torill; Lie, Asbjørn & Enoksen, Solveig [Vis alle 8 forfattere av denne artikkelen] (2023). Rapport BIOMANG. Tiltak for å bevare og fremme biologisk mangfold på campus Gimlemoen UiA. Universitetet i Agder. Fulltekst i vitenarkiv Vis sammendrag

  Tap av biologisk mangfold er en global krise (Ceballos et al. 2020, Hallmann et al. 2017) som truer samtlige av FNs bærekraftsmål, og UiA har som organisasjon forpliktet seg til å bidra til å nå disse målene. I tillegg til at alt liv har en egenverdi, gir også biologisk mangfold oss økonomiske og helsemessige fordeler. På campus har biologisk mangfold ytterligere en stor verdi innenfor formidling og undervisning, samt en verdi for universitetets omdømme. Mange utenlandske universiteter har utarbeidet planer for å sikre biologisk mangfold på sine campusområder. For eksempel har Kings College ved University of Cambridge erstattet kortklipt plen med blomstereng på sin campus. Dette har ikke bare ført til dokumentert positiv effekt på biologisk mangfold, men også lavere driftskostnader og økt trivsel og velvære blant studenter og ansatte (Marshall et al., 2023). Etter vår kunnskap har ingen universiteter i Norge presentert slike planer for sine campusarealer, selv om biologisk mangfold inngår i undervisningen. Ved å lage og implementere en biomangfoldsplan for universitetsområdet, har UiA muligheter til å være et foregangsuniversitet i Norge på dette området. Denne rapporten beskriver initiativet BIOMANG, iverksatt av Institutt for Naturvitenskaplige fag og Naturmuseet ved universitetet i Agder. Hensikten med initiativet er å bevare og fremme biologisk mangfold på campus Gimlemoen som en grunnleggende ressurs for fremtiden. I tillegg ønsker vi å legge til rette for kartlegging og formidling av kunnskap om biologisk mangfold. BIOMANG berører hele samfunnsoppdraget til UiA, både undervisning, forsknings- og utviklingsarbeid og samfunnskontakt og nyskaping (se figur 1). Initiativet vil også ha betydning for både de ansattes og studentenes arbeids- og læringsmiljø. BIOMANG handler om å bidra til det tverrfaglige satsningsområde Det grønne skiftet i UiAs strategiplan 2021-2024, men kan også ha betydning for alle de andre tverrfaglige satsingsområder: Teknologi og samfunnsendringer, Demokrati og medborgerskap, Helse og levekår, Læring og dannelse, og Kunst i samfunn. Formålet med denne rapporten er å synliggjøre hvordan biologisk mangfold inngår i UiAs samfunnsoppdrag og de ulike tverrfaglige satsingsområdene, samt komme med konkrete forslag til tiltak på ulike nivåer. I de neste avsnittene vil vi gå gjennom BIOMANGs involvering i undervisning, forsknings- og utviklingsarbeid, samfunnskontakt og arbeids- og læringsmiljø, før vi beskriver de ulike arbeidspakkene mer konkret. Vi er en prosjektgruppe som består av ansatte på Institutt for naturvitenskapelige fag og Naturmuseet, i tillegg til representanter fra drift og administrasjon. De som har vært med å utarbeide denne rapporten er: Anne Lien, Malene Østreng Nygård, Katharina Reionn Bjørnestøl, Solveig Enoksen, Torill Gjelsvik, Asbjørn Lie, Marte Sodeland og Roar Solheim. Beate Strøm Johansen har supplert prosjektgruppa med tekst. Anne Lien og Malene Østreng Nygård har vært prosjektledere og redaktører for rapporten.

• Haraldstad, Tormod; Neset, Philip Thomassen; Johansen, Kurt; Slettan, Audun & Sodeland, Marte (2021). Naturlig reetablering av laks i kystvassdrag mellom Otra og Mandalselva dokumentert ved elektrofiske og analyse av miljøDNA. Norsk institutt for vannforskning (NIVA). ISSN 9788257774073. Fulltekst i vitenarkiv Vis sammendrag

  I denne studien har vi dokumentert at laksen er tilbake i mange av kystvassdragene i Agder, og med dagens lave bestandssituasjon er slike reetableringer viktige. Bestandene i kystvassdragene er likevel sårbare, med få individer og små bekkesystemer. Mindre påvirkninger i nedbørfeltet og innblanding av rømt oppdrettslaks kan ha store konsekvenser for bestandene. Forsuringssituasjonen er generelt bedre i regionen og er antagelig bakgrunnen for at laksen igjen etablerer seg gjennom innvandring av laks fra de kalkede naboelvene. Vannkjemien er likevel begrensende for laksen i flere vassdrag i dag. Vi anbefaler at flere kystvassdrag kartlegges slik at vi får en oversikt over andelen laks i disse og hva som er styrende for forholdet mellom ungfisk av laks og aure i mindre vannsystemer. MiljøDNA kan være en viktig metode i en tidlig og bred screening, men tetthetsestimater og forholdet mellom artene bør foretas basert på tradisjonelt elektrofiske. Vi anbefaler at vannkjemien overvåkes i vassdrag med høyt innslag av laks, og at dosererkalking fra mindre anlegg bør vurderes.

• Sodeland, Marte; Lien, Sigbjørn & Kent, Matthew P. (2010). Genomic architecture and complex traits in norwegian red cattle. Norges miljø- og biovitenskapelige universitet (NMBU). ISSN 9788257509651. Fulltekst i vitenarkiv Vis sammendrag

  The predominant cattle breed in Norway, Norwegian Red cattle (NRF), is an admixed breed formed from local Norwegian breeds and imported animals from other Nordic breeds. The extensive phenotypic records for NRF represent a unique resource for studying genetic factors affecting complex traits of importance for animal production. Phenotypic records of traits related to milk production, meat production and fertility, as well as health traits such as veterinary treated clinical mastitis, are now kept for 96% of Norwegian cattle. Records of veterinary treated clinical mastitis have been kept for most NRF animals for the last three decades. Mastitis is inflammation of the mammary gland and is the most widespread disease affecting dairy cattle world-wide. Consequences of this disease include animal suffering, reduced milk quality, unwanted use of antibiotics and a more costly production. Main objective of the work described in this doctoral thesis has been to study the genomic architecture of the admixed NRF breed in order to understand the genetics underlying complex traits in cattle, particularly susceptibility to mastitis. The study was initiated with the genotyping of 2,589 NRF bulls for single-nucleotide polymorphisms (SNPs) using the Bovine Affymetrix 25k MIP SNP array. Construction of linkage maps provided a powerful resource for quality assessment of the bovine genome assembly Btau_4.0 and for investigations of recombination rates and linkage disequilibrium (LD) across the NRF genome. Differences between recent and historic recombination rates were used to identify genomic loci subjected to strong artificial selection in the observed pedigree. Reduced LD was found in NRF compared with other breeds included in the study. The high LD generally reported in cattle facilitates association mapping studies for detection of quantitative trait loci (QTLs) affecting complex traits. In order to detect QTLs affecting susceptibility to mastitis genome-wide association studies with over 17,000 SNPs were performed for occurrence of clinical mastitis (CM) in seven lactational time periods and for lactation average somatic cell score (SCS). Although there is a genetic correlation between CM and SCS, no consistencies were found between SNPs significantly associated with CM and those associated with lactation average SCS. Combined linkage and linkage disequilibrium analysis confirmed quantitative trait loci for CM on bovine chromosomes 2, 6, 14 and 20, with the highest test score for CM being found for a SNP at 90.67Mb on chromosome 6. In addition to the QTL for CM on chromosome 6, a QTL affecting milk protein yield (PY) has been found to coincide with the casein genes around 88Mb on this chromosome. Fine mapping gave highest test scores for PY in and around the casein genes CSN2 and CSN1S2 (at 88.33Mb and 88.41Mb), while highest test scores for CM were found within the region 89 to 91Mb. It has been suggested that a haplotype encompassing the casein genes, with a favorable effect on PY and an unfavorable effect on CM, was introduced into the NRF population through importation of a Holstein-Fresian bull (1606 Frasse) in the 1970s. High-throughput re-sequencing allowed for molecular characterization of the long range haplotype from 1606 Frasse and revealed plausible causal polymorphisms in the promoter region of the gene CSN1S2 and in a known regulatory motif in the 5’-flanking UTR of CSN1S2.

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