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  1. Carl André
  2. Lilian Franco Belussi
  3. Grégory Charrier
  4. Sam Dupont
  5. Anna Godhe
  6. Kerstin Johannesson
  7. Irene Kalchhauser
  8. Olga Kourtchenko - oral presentation
  9. Olga Kourtchenko - poster presentation
  10. Anna-Sara Krång
  11. Erica Leder
  12. Marina Panova
  13. Marina Rafajlovic
  14. Gry Sagebakken
  15. Helen Sköld
  16. Ola Svensson
  17. Alexander Ventura
  18. Filip Volckaert
  19. Anna-Lisa Wrange


Isolation by adaptation in Baltic cod

Carl André

Department of Biological and Environmental Sciences, University of Gothenburg

C. André & P. Berg, S. Jentoft, B. Star, K. Ring, H. Knutsen, S. Lien, K. Jakobsen.

Marine fishes generally show shallow population structures due to high dispersal and large population sizes. Genetic differentiation involved in local adaptation, on the other hand, is expected to be more pronounced in large populations.

Here, we investigated genomic signatures of local adaptation in Atlantic cod, a widely distributed marine fish with high fecundity and pelagic larvae, and thus high potential for gene flow. Using 8800 SNP loci located in both coding and non-coding genomic regions, as well as a set of candidate genes, we simultaneously investigated neutral and adaptive divergence in four cod populations along the environmental gradient from the fully marine North Sea to the low saline Baltic Sea.

Genome scan analysis identified 200 statistical outlier loci with high levels of divergence. Most of these outlier loci were also identified with a landscape genomic approach, and were associated with habitat differences in salinity, oxygen and temperature. Outlier loci were annotated to genes and regulatory networks involved in osmoregulation, indicating local adaptation to low salinity. The outliers were clustered to few single linkage groups suggesting genetic hitchhiking and the presence of genomic islands of divergence.

Baltic Sea cod was strongly differentiated from North Sea cod and fish collected in the salinity transition zone in Kattegat and Öresund, both for putatively neutral loci, and when using outlier loci only. The strong barrier to gene flow between Baltic cod and adjacent populations most likely result from effective reproductive isolation. Adaptation to the ecological conditions in the Baltic, such as egg buoyancy, sperm motility and spawning time constitutes a strong and effective reproductive barrier. Baltic cod may thus be viewed as an example of ongoing ecological speciation.

Functions of internal melanin in anurans and fishes

Lilian Franco Belussi

Department of Biological and Environmental Sciences, University of Gothenburg / São Paulo State University (UNESP), Brazil

Fish and amphibians have in addition to colourful skin also pigmented cells on internal organs and membranes. Two cells types are observed in internal organs: melanocytes and melanomacrophages. Melanocytes are similar to dermal melanocytes and they found on the surface of various organs and connective tissue. In contrast, melanomacrophages occur in hematopoietic organs and have phagocytic activity similar to macrophages. Both melanocytes and melanomacrophages produce and store melanin, however melanomacrophages also has catabolic substances (e.g. hemosiderin and lipofuscin). Internal melanocytes occur differentially between species, and seem to exhibit phylogenetic characteristics in some anuran lineages. Although there are some evidences that this visceral pigmentation may be related to accumulation of residual melanin and may has a role in the innate immune system, the functions of visceral pigmentation in fish and anurans are largely unknown, antioxidant functions, and protect tissues against DNA damage. Now we will test the potential functions of visceral pigmentation in protecting internal organs of anurans and fish against UV damage. Specifically, we will measure DNA damage and cell death in two lineages of pigmented cells; melanocytes and melanomacrophages. Furthermore, possible functions related to innate immunity will be evaluated by measuring phagocytosis and production of melanin after exposure to bacteria.

Title coming soon..

Greg Charrier
LEMAR (UMR CNRS 6539), European Institute for Marine Studies, Technopôle Brest-Iroise, France

Marine Evolution under Climate Change

Sam Dupont
Department of Biological and Environmental Sciences, University of Gothenburg

Genetic structure of algal blooms: Investigating the spring bloom of the Baltic Sea in spatial and temporal dimensions

Anna Godhe
Department of Biological and Environmental Sciences, University of Gothenburg

A Godhe1, C Sjöqvist2,3, S Sildever4, J Sefbom1, S Harðardóttir5, M Bertos6, C Bunse6, S Gross1, E Johansson1, PR. Jonsson1, S Khandan8, C Legrand6, N Lundholm5, K Rengefors8, I Sassenhagen7, S Suikkanen2, L Sundqvist1, A Kremp2
1 Department of Biological and Environmental Sciences, University of Gothenburg, Sweden
2 Finnish Environmental Institute/Marine Research Centre, Finland
3 Environmental and Marine Biology, Åbo Akademi University, Finland
4 Marine Systems Institute, Tallinn University of Technology, Estonia
5 Natural History Museum of Denmark, University of Copenhagen, Denmark
6 Linnæus University, Sweden
7 Aquatic Ecology, Lund University, Sweden

The Baltic Sea diatom spring bloom starts in coastal areas and after propagate into the open sea. An important question is if the bloom consists of one genetic population that moves as conditions improve, or if different populations bloom consecutively. To study temporal and spatial connectivity of the bloom-forming diatom Skeletonema marinoi we conducted four cruises along a southwest-northeast transect during the spring bloom 2013. 2000 individuals were isolated at ten fixed stations, and genotyped with eight microsatellite loci. F-statistics showed significant differentiation between the stations, refuting the null-hypothesis of panmixia. Pooled individuals from all four cruises at each station displayed significant isolation by distance. Populations sampled at the same station at different times were not differentiated, except at one station. A sea-scape approach displayed that gene flow and oceanographic connectivity were significantly correlated. Combined partial mantel test and RDA based variation partitioning highlighted the importance of salinity and phosphate concentration for spartial and temporal genetic structure.

Reproductive isolation in Littorina saxatilis contact zones

Kerstin Johannesson
Department of Biological and Environmental Sciences, University of Gothenburg

K. Johannesson, A. Westham, S. Baird, M. Ravinet, Z. Zagrevska, I. Sencic, R. Butlin.

This is a first a very preliminary report from the contact zone project started summer 2014 with the aim of describing the phenotypic and genetic characteristics of contact zones between crab and wave ecotype of Littorina saxatilis. From earlier genetic measurements we know that gene flow is reduced over contact zones down to 10-30% of normal gene flow. This can be due to habitat selection, differential selection, assortative mating and genetic incompatibilities. Here we present preliminary data showing no evidence for genetic incompatibilities but strong support for assortative mating based on snail size. As size is also under strong differential selection, this may be a multi-function trait (a "magic trait") that facilitates the development of reproductive isolation.

European bighead goby populations display large scale genetic homogeneity and small scale genetic differentiation in correlation with shipping patterns.

Irene Kalchhauser

Dr. Irene Kalchhauser, Prof. Dr. Patricia Holm
University of Basel, Departement of Environmental Sciences, Switzerland.

Ponto-Caspian gobies are a flock of bentic fish species that are currently on the move. Five species have been recorded outside their native range, some as far as North America. In Europe, they have populated Baltic and Northern European coasts as well as inland rivers as far west as France. They reach tremendous population densities and are able to deal with a wide range of environmental conditions.

Large scale population genetic analyses that would allow to trace their spread have so far focused on New World populations.

We genotyped more than 500 bighead goby from several established populations in North-Rhine Westphalia (NRW) and from several newly founded populations in Basel, Switzerland for 16 microsatellite loci. We find that the Basel river population is genetically closer to the NRW population than to the Basel harbor population.

Our results suggest that distant populations are closely connected by a vector. We therefore analyzed ship movements toward the Basel population. Indeed, the movement patterns of individual ship types may explain the observed patterns. A survey among local shipping companies unequivocally revealed that all ship types used on the Rhine transport substantial amounts of ballast water.

Taken together, our work provides the first genetic analysis of distant bighead goby populations in

Oral presentation:

Anthropogenic driven microevolution in a common diatom, Skeletonema marinoi

Olga Kourtchenko
Dept Chemistry and Molecular Biology, University of Gothenburg

Authors: Gross, S., Kourtchenko, O., Rajala, T., Tesson, S., Fernandez, L., Axelson-Fisk, M., Johannesson, K., Blomberg, A., Godhe, A

I will present our latest findings of phenotypic adaptation of S. marinoi to marine eutrophication. By tracing changes in growth response of these micro-algae to different levels of light and nutrition, we have uncovered a clear adaptive trend on the scale of the past 120 years. Our results are corroborated by parallel phenotypic responses in two independent populations. The project now continues towards the identification of genetic bases of the observed adaptive change.

Poster presentation: 

Quantitative phenotyping of Skeletonema marinoi growth on solid medium: a pilot study

Olga Kourtchenko
Dept Chemistry and Molecular Biology, University of Gothenburg

Authors: Kourtchenko, O., Rajala, T., Fernandez, L., Blomberg, A., Godhe, A

Micro-algal phenotyping still largely relies on labor-intense, low-throughput methods. We have been exploring streamlined, high-throughput techniques for growth quantification used for other microorganisms (bacteria, unicellular fungi), in particular, micro-cultivations in liquid medium. Here, I present the results of a pilot study aimed to gauge the feasibility of using solid-medium culturing method to reliably quantify Skeletonema’s growth characteristics, such as maximum growth rate and efficiency.

Behavioural, physiological and immunological responses of the Norway lobster exposed to hypoxia or manganese under the pressure of ocean acidification

Anna-Sara Krång
Department of Biological and Environmental Sciences, University of Gothenburg

Anna-Sara Krång, Hannah K Styf, Bodil Hernroth*, Susanne P Baden, Jonas Mattsson, Fredrik Jutfelt, Hannah LB Wood, Helen Nilsson Sköld, Anette Ungfors, Susanne P Eriksson

Department of Biological and Environmental Sciences, Kristineberg
University of Gothenburg, Sweden, *Kristianstad University, Sweden

Ocean acidification (OA) is a gradually increasing, ongoing process with great concern to marine biota. Yet we know very little about the combined effects of OA and other stressors such as spreading of oxygen depleted areas. The Norway lobster, Nephrops norvegicus, is an ecologically and commercially most important species found on coastal soft bottom sediments subjected to periodic hypoxia. Hypoxia in turn infers increased bioavailability of the heavy metal manganese that normally is bound the sediment. In this comprehensive study, we investigated possible interactions between longer-term exposure to elevated pCO2 at concentrations postulated by 2100, and more short-term exposure to hypoxia or manganese on different life stages of the Norway lobster. We show on behavioural effects such as disturbed food recognition, food search and CO2 avoidance, to effects on metabolic rate, embryonic heart rate and bacteriostatic suppression. Clearly, there are risks of great impact on lobster condition and biomass at these future stress scenarios. However, our results also demonstrate that susceptibility vary greatly between organisation levels as well as life stages.

The threespine stickleback methylome: Characterizing male and female differences

Erica Leder
Dept Biology, Div Genetics and Physiology, Turku University, Finland
Since males and females share the same genome in the autosomes, there are only a few potential ways to achieve differential expression: trans- acting regulators, ultimately initiated from the sex chromosome, or epigenetic regulation, specifically histone modification or DNA methylation.
DNA methylation involves the covalent modification of DNA and affects how a gene is regulated. Hypermethylation in a promoter region usually indicates repression of that gene.

Threespine stickleback exhibit large numbers of differentially expressed genes in brain and liver, however, even on the sex chromosomes there are no known unique genes. Therefore, the question remains, how are the male- and female-specific expression patterns differentially regulated? One possibility is through differential methylation. We examined the methylation patterns of males and females in liver and gonad tissue using whole-genome bisulfite sequencing in order to investigate male and female methylation differences.

Genomics of adaptation in marine snails Littorina saxatilis

Marina Panova
Department of Biological and Environmental Sciences, University of Gothenburg

The work is done by Anja Westram, Mark Ravinet, Marina Panova, Carl André, Kerstin Johannesson, Roger Butlin and the CeMEB bioinformatics team

Recent developments of sequencing techniques gave us the tools to study genomic patterns behind adaptations in different species. The questions to be answered include: How many genes are involved in adaptation? What types of genetic variations are responsible for adaptations? Does adaptation use pre-existing genetic variation or require new mutations?
Parallel evolution of ecotypes is especially interesting case when similar adaptive phenotypes repeatedly evolved in several places as response to divergent selection. However, whether these phenotypes have the same genetic architecture in all populations or can be produced by different alleles and may be even by different genes, is largely unknown. Few cases of repeated ecotype evolution studied so far, such as sticklebacks, give support to both.

The marine snails Littorina saxatilis have formed morphologically distinct Crab and Wave ecotypes in response to crab predation and wave exposure. These ecotypes evolved repeatedly in three geographic regions (the East coast of Britain, the Galician coast of Spain and the West coast of Sweden) and in many localities within each region. Recently, we used several molecular tools (genome scans by RNA-seq and RAD sequencing, re-sequencing of candidate loci by capture sequencing and gene expression analysis) together with the genome draft to understand the genetic changes underlying the adaptations in Littorina. As results, we found very low degree of genetic parallelism, suggesting that different genes and alleles produce adaptive phenotypes in different regions and even in different localities within the regions. It is likely that multiple selection agents, not only crabs and waves, affect the snails in the two habitats. The annotation of genes related to the ecotype divergence so far suggests that a broad range of organismal functions may be involved in this adaptation.

The statistics of phenotypic changes during adaptive divergence of partly isolated populations

Marina Rafajlovic
Department of Physics, University of Gothenburg

How to breed sand gobies for a common garden design. Work in progress.

Gry Sagebakken
Department of Biological and Environmental Sciences, University of Gothenburg

In order to prepare a linkage map and to test for the genetic basis of various traits such as salt tolerance, a common garden set up with several generations of progeny is needed. When using ecologically relevant species such as sand goby (Pomatoschistus minutus) no protocol for breeding and keeping gobies over generations exist. We prepared a new protocol for breeding and raising gobies from the Baltic Sea and Kattegat (high and low salinity). We started from standard protocols for fish breeding and old papers on breeding sand gobies. So far, we raised fry up to 6 days post hatch. We are working to fully close the breeding cycle. Some key factors are crucial for hatchling survival.

News on colors and color chnage in fish, and Havets Hus for outrech

Helen Nilsson-Sköld

Havets Hus, Lysekil & The Lovén Centre for Marine Sciences - Kristineberg

Fish comes in different colors. The most spectacular ones are found in the tropics, on coral reefs. Why is this so?

Here I have together with collegues around the world tried to address this question and other aspects of fish colors and color change. Moreover, I nowadays work 4 days a week at Havets Hus, a public marine aquarium in Lysekil. About 80.000 visitors pass this place /year and we are very active on social media. We propose Havets Hus as a potential outreach partner in research programs/projects as a natural link towards the public.

Local adaptation of reproductive traits as a starting point in ecological speciation

Ola Svensson
Department of Biological and Environmental Sciences, University of Gothenburg
Ola Svensson, Johanna Gräns, Malin Celander, Jonathan Havenhand, Erica Leder, Kai Lindström, Sofie Schöld, Cock van Oosterhout, Charlotta Kvarnemo
In animals with external fertilisation, the environment can exercise strong selection pressures not only on the soma of individuals, but also on their gametes and reproductive traits. Here we argue that reproductive traits can be under divergent selection, which can reduce the reproductive success of immigrants in the novel environment and curb gene flow. We conducted a series of experiments on the sand goby, Pomatoschistus minutus to understand how local adaptation of reproductive traits can affect reproductive success. We found that male sand gobies have a significantly reduced reproductive success outside their native salinity, which we interpret as evidence for local adaptation of sperm. Indeed, experiments showed that sperm of sand gobies perform poorly in non-native salinity. A computer model indicated that the effective rate of gene flow can be significantly reduced by selection on a reproductive trait. In some scenarios, reproductive isolation can evolve in a “feedback loop” of speciation, when adaptive divergence of the reproductive trait gradually reduces gene flow due to the fact that the viability of residents’ gametes continues to improve relative to that of immigrants. We propose that local adaptation of reproductive traits can be the starting point of ecological speciation.

Unaffected growth in mussel larvae exposed to acidified under-saturated seawater

Alexander Ventura
Department of Biological and Environmental Sciences, University of Gothenburg

Alexander Ventura, Sabrina Schulz and Sam Dupont

Ocean acidification (OA) is known to affect bivalve early life-stages. It is often assumed that aragonite saturation state (Ωa) is the main driver of the biological response. Our results confirmed that increasing seawater acidity and decreasing saturation state increased larval mortality rate and the percentage of abnormally developing larvae. No larvae reared at pHT ≈ 7.18 were able to reach the D-shell stage and their development appeared to be arrested at the trochophore stage. However, normally D-shaped larvae were observed in all other treatments including under-saturated seawater with Ωa as low as 0.54. These larvae grew significantly faster at lower pHT despite increased energy costs associated with compensatory calcification to fight against dissolution. Overall, our results suggest a shift in energy allocation toward growth in larvae exposed to ocean acidification and can be interpreted in the context of the desperate larvae hypothesis.

Is there a co-phylogeographic signal in Gyrodactylus flatworms and their sand goby host?

Filip Volckaert
University of Leuven, Laboratory of Biodiversity and Evolutionary Genomics, Belgium

Tine Huyse1,2, Merel Oeyen1, Maarten H.D. Larmuseau1,3 & Filip A.M. Volckaert1,4

1 University of Leuven, Laboratory of Biodiversity and Evolutionary Genomics, Belgium
2 Biology Department, Royal Museum for Central Africa, Belgium
3 University of Leuven, Laboratory of Forensic Genetics and Molecular Archaeology, Belgium
4 University of Gothenburg, Department of Biology and Environmental Sciences, Sweden

We performed a comparative phylogeographic study on the monogenean flatworm Gyrodactylus gondae spp., and its sand goby host Pomatoschistus minutus (Gobiidae). G. gondae is a host-specific parasite that lives in close association with its hosts, has a direct life cycle and a very short generation time. These properties are expected to increase the opportunity to track the genealogical history of the host with genetic data of the parasite. To investigate this hypothesis, we sampled Gyrodactylus specimens from 10 sand goby populations (n=404) along the Atlantic coasts of Europe. We sequenced a 460 bp cytochrome c oxidase subunit II (coxII) fragment of 92 G. gondae harvested on five sand goby populations. Haplotype diversity was lowest in the Irish Sea while nucleotide diversity was highest in the Southern North Sea, a pattern also found for the host population based on previously published cytochrome b sequences of 850 bp. Pair-wise population differentiation was higher in the parasite than in the host but host and parasite phylogeographic network were not concordant. The parasite network showed differentiation of northern populations but was characterized by many extinctions and/or missing haplotypes. A possible explanation for these observations could be that population size fluctuations in the parasite populations result in frequent extinctions and genetic drift, leading to haplotype loss. It is therefore not possible in this particular host parasite system to use Gyrodactylus as a looking glass for elucidating the host’s history.

The story of a hitchhiker: population genetic patterns in the invasive barnacle Balanus improvisus

Anna-Lisa Wrange
Department of Biological and Environmental Sciences, University of Gothenburg

Understanding the ecological and evolutionary forces that determine the genetic structure and spread of invasive species is a key component of invasion biology. The bay barnacle, Balanus improvisus, is one of the most successful aquatic invaders worldwide, and is characterised by broad environmental tolerance. Although the species can spread through natural larval dispersal, human-mediated transport through (primarily) shipping has almost certainly contributed to the current global distribution of this species. Despite its worldwide distribution, nothing is known about the phylogeography of this species. Here, we have characterised the population genetic structure and potential dispersal dynamics of the barnacle B. improvisus, and describe how human-mediated spreading via shipping as well as natural larval dispersal may have contributed to observed genetic variation. We used both mitochondrial DNA (cytochrome c oxidase subunit I: COI) and nuclear microsatellites to characterize the genetic structure in 14 populations of B. improvisus on a global and regional (Baltic Sea) scale. Genetic diversity was high in most populations, and many haplotypes were shared between populations on a global scale, indicating that long-distance dispersal (presumably through shipping and other anthropogenic activities) has played an important role in shaping the population genetic structure of this cosmopolitan species. We found indications of founder effects only in populations from the Black Sea, Caspian Sea and the northern Baltic Sea. We could not clearly confirm prior claims that B. improvisus originates from the western margins of the Atlantic coasts; although there were indications that Argentina could be part of a native region. In addition to dispersal via shipping, we show that natural larval dispersal may play an important role for further colonisation following initial introduction. 

Page Manager: Eva Marie Rödström|Last update: 4/20/2015

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