| 1. |
- Andersson, Leif, et al.
(författare)
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Ecological adaptation in cod and herring and possible consequences of future climate change in the Baltic Sea
- 2023
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Ingår i: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 10
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Forskningsöversikt (refereegranskat)abstract
- The Atlantic herring and Atlantic cod are two marine fish species that have successfully adapted to the brackish Baltic Sea, and the former is able to spawn in near-freshwater conditions in the inner Gulf of Bothnia. Here, we review the state of current knowledge concerning ecological adaptation in the two species and make an attempt to predict how they will be able to cope with future climate change. Previous whole genome sequencing studies in Atlantic herring have revealed hundreds of genetic loci underlying ecological adaptation, including several loci that show very strong associations to variation in salinity and temperature. These results suggest the existence of standing genetic variation available for adaptation to a changing environment. However, although Atlantic herring probably has the genetic potential to adapt, its future status also depends on how climate change will affect plankton production and competing species, such as sprat and three-spined stickleback. In cod, the situation is challenging, as there is only one true Baltic population, spawning east of Bornholm and then dispersing towards the east and north. This Baltic cod population is threatened by overfishing, low oxygen levels in benthic waters and generally bad physiological condition of individual fish, in addition to being completely isolated from gene flow from nearby cod populations at the entrance of the Baltic Sea.
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| 2. |
- Barth, Julia M.I., et al.
(författare)
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Genome architecture enables local adaptation of Atlantic cod despite high connectivity
- 2017
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 26:17, s. 4452-4466
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Tidskriftsartikel (refereegranskat)abstract
- Adaptation to local conditions is a fundamental process in evolution; however, mechanisms maintaining local adaptation despite high gene flow are still poorly understood. Marine ecosystems provide a wide array of diverse habitats that frequently promote ecological adaptation even in species characterized by strong levels of gene flow. As one example, populations of the marine fish Atlantic cod (Gadus morhua) are highly connected due to immense dispersal capabilities but nevertheless show local adaptation in several key traits. By combining population genomic analyses based on 12K single nucleotide polymorphisms with larval dispersal patterns inferred using a biophysical ocean model, we show that Atlantic cod individuals residing in sheltered estuarine habitats of Scandinavian fjords mainly belong to offshore oceanic populations with considerable connectivity between these diverse ecosystems. Nevertheless, we also find evidence for discrete fjord populations that are genetically differentiated from offshore populations, indicative of local adaptation, the degree of which appears to be influenced by connectivity. Analyses of the genomic architecture reveal a significant overrepresentation of a large ~5 Mb chromosomal rearrangement in fjord cod, previously proposed to comprise genes critical for the survival at low salinities. This suggests that despite considerable connectivity with offshore populations, local adaptation to fjord environments may be enabled by suppression of recombination in the rearranged region. Our study provides new insights into the potential of local adaptation in high gene flow species within fine geographical scales and highlights the importance of genome architecture in analyses of ecological adaptation.
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| 3. |
- Berdan, Emma L, 1983, et al.
(författare)
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A metabarcoding analysis of the wrackbed microbiome indicates a phylogeographic break along the North Sea-Baltic Sea transition zone
- 2023
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Ingår i: Environmental Microbiology. - 1462-2912. ; 25:9, s. 1659-73
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Tidskriftsartikel (refereegranskat)abstract
- Sandy beaches are biogeochemical hotspots that bridge marine and terrestrial ecosystems via the transfer of organic matter, such as seaweed (termed wrack). A keystone of this unique ecosystem is the microbial community, which helps to degrade wrack and re-mineralize nutrients. However, little is known about this community. Here, we characterize the wrackbed microbiome as well as the microbiome of a primary consumer, the seaweed fly Coelopa frigida, and examine how they change along one of the most studied ecological gradients in the world, the transition from the marine North Sea to the brackish Baltic Sea. We found that polysaccharide degraders dominated both microbiomes, but there were still consistent differences between wrackbed and fly samples. Furthermore, we observed a shift in both microbial communities and functionality between the North and Baltic Sea driven by changes in the frequency of different groups of known polysaccharide degraders. We hypothesize that microbes were selected for their abilities to degrade different polysaccharides corresponding to a shift in polysaccharide content in the different seaweed communities. Our results reveal the complexities of both the wrackbed microbial community, with different groups specialized to different roles, and the cascading trophic consequences of shifts in the near shore algal community.
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| 4. |
- Blakeslee, A. M. H., et al.
(författare)
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Population structure and phylogeography of two North Atlantic Littorina species with contrasting larval development
- 2021
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 168:7
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Tidskriftsartikel (refereegranskat)abstract
- Phylogeography provides insights into how historical and contemporary processes influence the genetic structure and gene flow in marine organisms around the globe. In benthic marine invertebrates, a species' reproductive strategy can strongly impact phylogeographic patterns and distribution, with some direct-developing (non-planktonic) dispersers demonstrating strong genetic structure but also broad geographic spread. While seemingly paradoxical, past work has shown ovoviviparous species, like Littorina saxatilis, can be more successful colonizers of remote locations than species with planktonic larvae, like L. littorea. Both Littorina species overlap in much of their North Atlantic ranges but have different colonization histories: L. saxatilis is native on both North Atlantic coasts and islands, and L. littorea is native to the eastern Atlantic but introduced to the west. Using an extensive mitochondrial dataset (1236 sequences; 85 sites), we examined how their opposing reproductive strategies correspond to their distributions and phylogeographies. Littorina saxatilis exhibited a heterogeneous genetic structure reflecting post-glacial recolonization from multiple refugial sites, while L. littorea had a homogeneous structure with a post-glacial history characterized by recolonization from one main refugial area in the northeast Atlantic. Further, haplotype diversity was significantly depressed in northwest Atlantic L. littorea populations, signifying a strong bottleneck characteristic of a human-mediated introduction. In contrast, haplotype diversity in L. saxatilis was similar between the two regions, demonstrating long-term history on both coasts. Thus, our study suggests contrasting life-history characteristics were a major structuring force in the phylogeographic patterns of these related species following large-scale disturbances (natural and anthropogenic) that compel contraction and redistribution over large areas.
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| 5. |
- Butlin, Roger, 1955, et al.
(författare)
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PARALLEL EVOLUTION OF LOCAL ADAPTATION AND REPRODUCTIVE ISOLATION IN THE FACE OF GENE FLOW
- 2014
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Ingår i: Evolution. - : Wiley. - 0014-3820. ; 68:4, s. 935-949
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Tidskriftsartikel (refereegranskat)abstract
- Parallel evolution of similar phenotypes provides strong evidence for the operation of natural selection. Where these phenotypes contribute to reproductive isolation, they further support a role for divergent, habitat-associated selection in speciation. However, the observation of pairs of divergent ecotypes currently occupying contrasting habitats in distinct geographical regions is not sufficient to infer parallel origins. Here we show striking parallel phenotypic divergence between populations of the rocky-shore gastropod, Littorina saxatilis, occupying contrasting habitats exposed to either wave action or crab predation. This divergence is associated with barriers to gene exchange but, nevertheless, genetic variation is more strongly structured by geography than by ecotype. Using approximate Bayesian analysis of sequence data and amplified fragment length polymorphism markers, we show that the ecotypes are likely to have arisen in the face of continuous gene flow and that the demographic separation of ecotypes has occurred in parallel at both regional and local scales. Parameter estimates suggest a long delay between colonization of a locality and ecotype formation, perhaps because the postglacial spread of crab populations was slower than the spread of snails. Adaptive differentiation may not be fully genetically independent despite being demographically parallel. These results provide new insight into a major model of ecologically driven speciation.
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| 6. |
- Canbäck, Björn, et al.
(författare)
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The Littorina sequence database (LSD) - an online resource for genomic data.
- 2012
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 12, s. 142-148
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Tidskriftsartikel (refereegranskat)abstract
- We present an interactive, searchable expressed sequence tag database for the periwinkle snail Littorina saxatilis, an upcoming model species in evolutionary biology. The database is the result of a hybrid assembly between Sanger and 454 sequences, 1290 and 147 491 sequences respectively. Normalized and non-normalized cDNA was obtained from different ecotypes of L. saxatilis collected in the UK and Sweden. The Littorina sequence database (LSD) contains 26 537 different contigs, of which 2453 showed similarity with annotated proteins in UniProt. Querying the LSD permits the selection of the taxonomic origin of blast hits for each contig, and the search can be restricted to particular taxonomic groups. The database allows access to UniProt annotations, blast output, protein family domains (PFAM) and Gene Ontology. The database will allow users to search for genetic markers and identifying candidate genes or genes for expression analyses. It is open for additional deposition of sequence information for L. saxatilis and other species of the genus Littorina. The LSD is available at http://mbio-serv2.mbioekol.lu.se/Littorina/.
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| 7. |
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| 8. |
- De Wit, Pierre, 1978, et al.
(författare)
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Diet-dependent gene expression highlights the importance of Cytochrome P450 in detoxification of algal secondary metabolites in a marine isopod
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Isopods of the genus Idotea have an unusual ability to feed on algae containing high amounts of chemical defense molecules, such as species of the genera Fucus and Ulva. In this study, we compared gene expression patterns of Idotea balthica individuals fed with Fucus vesiculosus to individuals fed with Ulva lactuca. We generated the rst-ever transcriptome assembly for this species, and found 3,233 di erentially expressed genes across feeding regimes. However, only a handful of biological functions were enriched with regard to di erentially expressed genes, the most notable being “alkaloid metabolic process”. Within this category, we found eight di erentially expressed cytochrome P450 (CYP) unigenes, all of which had a higher expression in the U. lactuca diet treatment. A phylogenetic analysis showed that the di erentially expressed CYP genes are closely related to a CYP gene described from the hepatopancreas of the spiny lobster Panulirus argus, and we hypothesize that these transcripts are involved in metabolite detoxi cation. This is a rst step in the understanding of this algae-grazer interaction, and will form a basis for future work to characterize cytochrome P450 functioning in marine crustaceans.
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| 9. |
- De Wit, Pierre, 1978, et al.
(författare)
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Spatial genetic structure in a crustacean herbivore highlights the need for local considerations in Baltic Sea biodiversity management
- 2020
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4563 .- 1752-4571. ; 13:5, s. 974-990
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Tidskriftsartikel (refereegranskat)abstract
- Incorporating species' eco-evolutionary responses to human-caused disturbances remains a challenge in marine management efforts. A prerequisite is knowledge of geographic structure and scale of genetic diversity and connectivity—the so-called seascape genetic patterns. The Baltic Sea is an excellent model system for studies linking seascape genetics with effects of anthropogenic stress. However, seascape genetic patterns in this area are only described for a few species and are completely unknown for invertebrate herbivores, which constitute a critical part of the ecosystem. This information is crucial for sustainable management, particularly under future scenarios of rapid environmental change. Here, we investigate the population genetic structure among 31 locations throughout the Baltic Sea, of which 45% were located in marine protected areas, in one of the most important herbivores of this region, the isopod crustacean Idotea balthica, using an array of 33,774 genome-wide SNP markers derived from 2b-RAD sequencing. In addition, we generate a biophysical connectivity matrix for I. balthica from a combination of oceanographic current models and estimated life history traits. We find population structure on scales of hundreds of kilometers across the Baltic Sea, where genomic patterns in most cases closely match biophysical connectivity, indicating passive transport with oceanographic currents as an important mean of dispersal in this species. We also find a reduced genetic diversity in terms of heterozygosity along the main salinity gradient of the Baltic Sea, suggesting periods of low population size. Our results provide crucial information for the management of a key ecosystem species under expected changes in temperature and salinity following global climate change in a marine coastal area. © 2019 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.
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| 10. |
- Duvefelt, Kenneth B. K., et al.
(författare)
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Towards simultaneous measurements of skin friction and contact area : Results and experiences
- 2015
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Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - : Sage Publications. - 1350-6501 .- 2041-305X. ; 229:3, s. 230-242
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Tidskriftsartikel (refereegranskat)abstract
- This article investigates one of the important parameters when designing for feel, namely the friction coefficient. An experiment was performed to evaluate how fringe projection could be used to investigate the topography of the fingertip, especially while in contact and sliding on a smooth surface. By allowing this smooth surface to be a small sheet of glass, a topographic camera could take pictures through it. The glass was also connected to a universal force gauge to measure normal and tangential forces from which the coefficient of friction could be calculated. The intention was to get dependable data on the forces, coefficient of friction, apparent contact area and actual contact area. This set-up was tested using 66 students who used one and three fingers in both dry and wet conditions and with a rubber glove. In order to measure natural everyday friction, they were not given any particular instructions on how to clean or slide their fingers. This method resulted in a much higher variation in friction coefficients than has been found in previous research. In particular, many higher values were noticed. This illustrates that the friction coefficient is a very hard parameter to rely on when it comes to designing surfaces for feel.
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