Publications (8) View all
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Article: A proteomics approach reveals divergent molecular responses to salinity in populations of European whitefish (Coregonus lavaretus).
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ABSTRACT: Osmoregulation is a vital physiological function for fish, as it helps maintain a stable intracellular concentration of ions in environments of variable salinities. We focused on a primarily freshwater species, the European whitefish (Coregonus lavaretus), to investigate the molecular mechanisms underlying salinity tolerance and examine whether these mechanisms differ between genetically similar populations that spawn in freshwater vs. brackishwater environments. A common garden experiment involving 27 families in two populations and five salinity treatments together with a large-scale, high-resolution mass spectrometry experiment that quantified 1500 proteins was conducted to assess phenotypic and proteomic responses during early development, from fertilization until hatching, in the studied populations. The populations displayed drastically different phenotypic and proteomic responses to salinity. Freshwater-spawning whitefish showed a significantly higher mortality rate in higher salinity treatments. Calcium, an ion involved in osmotic stress sensing, had a central role in the observed proteomic responses. Brackishwater-spawning fish were capable of viable osmoregulation, which was modulated by cortisol, an important seawater-adaptation hormone in teleost fish. Several proteins were identified to play key roles in osmoregulation, most importantly a highly conserved cytokine, tumour necrosis factor, whereas calcium receptor activities were associated with salinity adaptation. These results imply that individuals from these populations are most likely adapted to their local environments, even though the baseline level of genetic divergence between them is low (F(ST)=0.049). They also provide clues for choosing candidate loci for studying the molecular basis of salinity adaptation in other species. Further, our approach provides an example of how proteomic methods can be successfully used to obtain novel insights into the molecular mechanisms behind adaptation in non-model organism.Molecular Ecology 04/2012; 21(14):3516-30. · 5.52 Impact Factor -
Article: A newly isolated family of short interspersed repetitive elements (SINEs) in coregonid fishes (whitefish) with sequences that are almost identical to those of the SmaI family of repeats: possible evidence for the horizontal transfer of SINEs.
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ABSTRACT: The SmaI family of repeats is present only in the chum salmon and the pink salmon, and it is not present in five other species in the same genus or in other species in closely related genera. In the present study, we showed that another short interspersed repetitive elements (SINEs) family, which is almost identical to the SmaI family, is present in all fishes in the subfamily Coregoninae, being regarded as the most primitive salmonids. This new family of SINEs was designated the SmaI-cor family (SmaI family of repeats in coregonids). The consensus sequence of the SmaI-cor family was found to be 98.6% homologous to that of the SmaI family. Accordingly, it is difficult to explain the high degree of homology between these two families of SINEs by any mechanism other than the horizontal transfer of SINEs. The estimates of the rate of neutral mutation of nuclear genes, comparing chum salmon and European whitefish, confirmed this possibility. Our results strongly suggest that a member(s) of the SmaI-cor family might have been transferred horizontally from one coregonid species to a common ancestor of chum and pink salmon or to these two species independently, to allow subsequent amplification of the SmaI family in their respective genomes.Genetics 06/1997; 146(1):355-67. · 4.01 Impact Factor -
Article: Amplification of distinct subfamilies of short interspersed elements during evolution of the Salmonidae.
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ABSTRACT: There are at least three different kinds of short interspersed repetitive elements in salmonid genomes. Of these, members of the HpaI family are found to be most widely distributed in salmonid species. The HpaI family is present with high copy numbers in all members of the subfamily Salmoninae, such as salmon, trout and charr. In order to determine whether the amplification of the Hpa sequence occurred rapidly within a short evolutionary period or gradually, over the long term, a search was made for Hpa sequences in primitive salmonids; namely, grayling and whitefish. A grayling species has fivefold fewer copies of these sequences than the Salmoninae species, whereas several whitefish species have 200-fold to 20-fold fewer copies than the Salmoniae species. Characterization of the Hpa sequences in these species allowed us to recognize two distinct Hpa subfamilies on the basis of diagnostic substitutions as well as a new short interspersed element with an Hpa-related sequence. The distribution of these sequences revealed that distinct members of the HpaI or Hpa-related family were amplified during establishment of each subfamily lineage in a manner very similar to the amplification of the human Alu family. We provide evidence for the validity of a model that involves "multiple source genes" to explain diagnostic substitutions of the Hpa subfamilies and the timing of their appearance during evolution.Journal of Molecular Biology 10/1994; 241(5):633-44. · 4.00 Impact Factor -
Article: Evolutionary history of the European whitefish Coregonus lavaretus (L.) species complex as inferred from mtDNA phylogeography and gill-raker numbers.
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ABSTRACT: We compared mitochondrial DNA and gill-raker number variation in populations of the European whitefish Coregonus lavaretus (L.) species complex to illuminate their evolutionary history, and discuss mechanisms behind diversification. Using single-strand conformation polymorphism (SSCP) and sequencing 528 bp of combined parts of the cytochrome oxidase b (cyt b) and NADH dehydrogenase subunit 3 (ND3) mithochondrial DNA (mtDNA) regions, we documented phylogeographic relationships among populations and phylogeny of mtDNA haplotypes. Demographic events behind geographical distribution of haplotypes were inferred using nested clade analysis (NCA) and mismatch distribution. Concordance between operational taxonomical groups, based on gill-raker numbers, and mtDNA patterns was tested. Three major mtDNA clades were resolved in Europe: a North European clade from northwest Russia to Denmark, a Siberian clade from the Arctic Sea to southwest Norway, and a South European clade from Denmark to the European Alps, reflecting occupation in different glacial refugia. Demographic events inferred from NCA were isolation by distance, range expansion, and fragmentation. Mismatch analysis suggested that clades which colonized Fennoscandia and the Alps expanded in population size 24 500-5800 years before present, with minute female effective population sizes, implying small founder populations during colonization. Gill-raker counts did not commensurate with hierarchical mtDNA clades, and poorly with haplotypes, suggesting recent origin of gill-raker variation. Whitefish designations based on gill-raker numbers were not associated with ancient clades. Lack of congruence in morphology and evolutionary lineages implies that the taxonomy of this species complex should be reconsidered.Molecular Ecology 01/2006; 14(14):4371-87. · 5.52 Impact Factor -
Article: Fish deformities and pollution in some Swedish waters
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ABSTRACT: Ambio, vol. 14, nr. 1, 32-35
