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MS projects in Aquatic biology and fisheries

Arnar Pálsson, 24/07/2025

The new cohort in MS programme on Aquatic biology and fisheries can choose from a variety of projects.

The coordinator of the programme at the University of Iceland is Dr. Haseeb Randhawa. He maintains a list of projects that students can request to work on.

Here we list three projects that are also offered to students in this programme in the fall of 2025.

Ecological influence on evolution of feeding elements in sympatric morphs  

Ecological opportunities can be exploited by organisms and leading to evolutionary divergence and even speciation. Fish show an impressive diversity in feeding specializations, seeming resulting from evolution and ecological opportunities.  Data suggest substantial level of phenotypic parallelism in body- and head-shape in Arctic charr, when they radiate into diverse morphs in northern lakes. The research project centers on questions at the intersection of ecological, evolutionary and developmental biology or anatomy. The aim is to study morphological variation in sympatric charr to study the ecological influence on feeding morphology (teeth and bone shape). The over arching questions are: Which feeding traits differ consistently between sympatric morphs across lakes? Does plasticity in feeding traits differ between benthic and pelagic morphs? What is the pattern of evolutionary divergence in upper and lower jaw traits in Arctic charr?  The approach will be based on ecological sampling, dissections and morpological and statistical analyses including the use of geometric morphometrics. The student will work with other graduate students in the Arctic charr group at the University of Iceland, and scientsist at the Freshwater division of MFRI and at Universities in Canada. The candidate should have biology or ecology background, numerical skills a strong suit, and have interest in anatomical diversity, ecology, evolution and development.

maxilla, premaxilla, palatine, supramaxilla

Supervisors: Arnar Pálsson and Gudbjörg Ósk Jónsdóttir (https://orcid.org/0009-0008-0502-5553) at University of Iceland. 

Location: Field work in South-west Iceland and lab work in Reykjavík 

Examples of related studies. 

Jónsdóttir GÓ, von Elm L-M, Ingimarsson F, Tersigni S, Snorrason SS, Pálsson A, et al. (2024) Diversity in the internal functional feeding elements of sympatric morphs of Arctic charr (Salvelinus alpinus). PLoS ONE 19(5): e0300359. https://doi.org/10.1371/journal.pone.0300359  

 

Genomics of rapid diversification in craniofacial traits related to feeding 

The genetic raw material for adaptive evolution can now be studied with whole genome sequencing, and the patterns of positive selection detected in genomes of non-model organisms. Systems with extensive sympatric and allopatric polymorphism can be studied with these methods, to map out patterns of divergence and highlight loci and genomic regions that have been shaped by positive selection in response to ecological diversity. Arctic charr is known for considerable polymorphism and substantial phenotypic parallelism in feeding and body morphology. The aim of this project is to explored the genomics related to craniofacial diversity in sympatric Arctic charr, in reference to anadromous populations (putative ancestors). The research questions are the following: i) which loci and molecular pathways separate ecologically specialized morphs, ii) what is the role of structural variations in maintaining morph separation, and iii) when in development do adaptive traits emerge? The project involves sampling fish in their habitat, processing them and working with students doing phenotypic analyses. The main effort will be DNA isolation and analyses of whole genome sequencing data from the sampled populations, using bioinformatic and population genetic tools and programmes. The ideal candidate should have biology and genetics background, strong bioinformatic and numerical skills are required. 

Comparison of distributions of Heterozygosity by morphs and lakes

Supervision: Arnar Pálsson, Zophonías O. Jónsson and Gudbjörg Ósk Jónsdóttir at the University of Iceland. 

Location: Sampling in South-west Iceland, lab work and analyses in Reykjavík 

Examples of related studies. 

Han Xiao, Arnar Palsson, Zophonías Oddur Jónsson, et al. Gene flow and habitat heterogeneity shape coexistence dynamics of Arctic charr morphs in connected lakes. Authorea. December 27, 2024.
DOI: 10.22541/au.173531304.47377188/v1

Jónsdóttir GÓ, von Elm L-M, Ingimarsson F, Tersigni S, Snorrason SS, Pálsson A, et al. (2024) Diversity in the internal functional feeding elements of sympatric morphs of Arctic charr (Salvelinus alpinus). PLoS ONE 19(5): e0300359. https://doi.org/10.1371/journal.pone.0300359  

 

Migration patterns and habitat utilization of ecologically diverse fish 

Anadromous fihs like salmonids spawn in freshwater, but most return to sea for feeding and growing. While atlantic salmon and brown trout feed in the open seas, arctic charr tends to use coastal habitats and estuaries, at least in Iceland. Arctic charr also migrates into rivers to over winter. The three species, the native salmonids in Iceland, also seem to use different parts of the water ways for spawning and as juvenile habitats. The aim of the project is to explore the habitat utilization and migration patterns of Arctic charr in Icelandic waterways. The main research questions are, i) how widely do the Arctic charr migrate within a major system of waterways in West Iceland? ii) which habitats to the fish choose in different times of the year, and iii) what are the migration patterns (time of year and day) around the spawning grounds in the fall? The questions will be addressed with, new ecological surveys and tagging, fish counter deployment and data gathering, and already collected tracking data on individual fish. The candidate should have background in fish biology or ecology, and ideally have strong numerical skills.

Vífilsdalsá í dölum, typical charr river in west Iceland.

Supervisors: Johannes Guðbrandsson (Marine and Freshwater research institute, https://orcid.org/0000-0002-2231-0910) and Arnar Pálsson at University of Iceland. 

Location: West Iceland (Hvanneyri) and Reykjavík. 

Examples of related studies. 

Guðbjörg Ósk Jónsdóttir, Benóný Jónsson, Magnús Jóhannsson og Arnar Palsson. 2024. Uppeldissvaeði laxfiska í Þingvallavatni og tengdum ám / Areas used by Salmonid juveniles in Lake Þingvallavatn and connected rivers. December 2024. 3-4. DOI: 10.33112/nfr.94.3.2

Silja Bára for rector

Arnar Pálsson, 10/03/2025

Wrote a letter of support for the candidacy of Silja Bara Omarsdottir for rector of the University of Iceland.

On icelandic news website Visir.is Mann­legi rektorinn Silja Bára - Vísir

Lúsmý, maurar og fleiri dýr

Arnar Pálsson, 30/06/2023

Nýsköpunarsjóður námsmanna gerir fjórum líffræðinemar og BS líffræðingar kleift að verkefnum um skordýr á Íslandi við Líffræðistofu Háskóla Íslands nú í sumar.

Við höfum áður fjallað um maurarannsóknir en auk þess er kastljósinu nú beint að lúsmýi og ávaxtaflugum. Það eru nýlegir landnemar hérlendis. Lúsmýið er alræmt fyrir bit og almenn leiðindi, en ávaxtaflugur eru dýrkaðar og dáðar vegna fegurðar sinnar og fengileiks. Sumir eru reyndar smeykir við ávaxtaflugur, en þær bíta ekki fólk, bera ekki sjúkdóma og verða bara til ama ef þær verpa í bananann sem við gleymdum undir ískáp.

Í lúsmý verkefninu er ætlunin að kanna hvenær sumarsins þær koma fram, hvort um sé að ræða einn eða tvo toppa klaksins, hvaða búsvæðum flugurnar klekjast helst úr og hver dreifing þeirra á landsvísu er. Beitt verður aðferðum skordýrafræði og stofnerfðafræði. Hér að neðan eru myndir af klakgildrum og vettvangi rannsókna í Kjósinni.

The mesopelagic zone - 5 day course in May.

Arnar Pálsson, 20/01/2023
2 ECT 5-DAY SUMMER SCHOOL COURSE
The mesopelagic zone (between 200-1000m depth) is the habitat of the largest fish biomass in the ocean.
Mesopelagic fish likely hold a key role in global climate change by participating in the largest migration in the animal kingdom, transporting and storing carbon into the deep sea.

Credit: Leif Grimsmo, SINTEF Ocean

About the course
The SUMMER (Sustainable Management of Mesopelagic Resources, 2019-2024) EU project aims to evaluate if and how mesopelagic resources can be sustainably exploited.
To share the knowledge of the mesopelagic zone, experts from the SUMMER project have arranged a 5-day summer school course for 2 ECT credits, with the Marine and Freshwater Research Institute and the University of Iceland, in Iceland May 22nd – May 26th 2023.
The course will feature lectures from world-leading experts on mesopelagic research, engaging discussions, as well as hands-on laboratory work on mesopelagic fishes – in addition to the dissection of a marine mammal, apex predator of mesopelagic fish.
After completing the course
Students will be familiar with:
• Biology and Ecology of the Mesopelagic Zone
• Taxonomy and Diversity of Mesopelagic Fish
• Mesopelagic Fisheries (Economy, Governance,
Technology)
• Dissection of Mesopelagic Fish and Mammals
Students will develop valuable knowledge of one of the most understudied ecosystems in the world’s oceans, meet worldwide leaders in mesopelagic research, and study in an international group.
Students will also get to experience Reykjavik, the capital of Iceland in May – during a wonderfully bright spring.
The course itself is free for participatnts, but travel expenses (food, lodgings, and transport) must be covered individually.
International students are encouraged to apply, and housing is available on the university campus.
For more information
Website: www.summerh2020.eu
Email: hrandhawa@hi.is

First results from scanning of charr juveniles

Arnar Pálsson, 06/09/2021

We have started a collaboration with Benedikt Hallgrimsson and his colleagues at University of Calgary, Marta Vidal-Garcia and Avrille Aiello.

They are scanning one year old Arctic charr that Sarah Steele raised in her plasticity experiment. That study focused on comparing morphological differences and plastic responses between derived and ancestral populations of charr, to understand differences in growth, allometric changes in shape and inheritance of these traits.

The pilot project with the Hallgrimsson lab focuses on comparing three morphs, the anadromous charr from Fljota (putative ancestral morph) and two derived morphs from Lake Thingvallavatn, the Large Benthic and Planktivorous charr. They were all raised on the same diet, and are similar in size. First scans from Avrille and Marta, of an LB individual, are shown below.

The top figure is lateral view (with an angle slightly from the front) and the lower figure is a view from the top of the head (first vertebrae can be seen on the right).

The fishes were about 1 year old when killed and frozen. Fixed in 10% NPF for 10 days, prior to CT scanning.

In this phase of the project we will scan 20 fishes per morph, and characterize the diversity in shape of the feeding related bones, snout area and the cranium.

And hopefully be able to scan the other treatment, wild fishes and progeny from crosses in the future if funding becomes available.

Trancriptional co-option, transcriptional decay and the principles of regulatory evolution.

Arnar Pálsson, 19/01/2018

Trancriptional co-option, transcriptional decay and the principles of regulatory evolution.

Arnar Pálsson, Institute of biology, University of Iceland

Marcos A. Antezana, Institute of biology, University of Iceland

PALSSON A. & ANTEZANA M. 2017: Transcriptional co-option, transcriptional decay and the principles of regulatory evolution. Abstract. - In: W ERTH S. & O BERMAYER W. (editors). Lichen Genomics Workshop II. Institute of Plant Sciences, University of Graz, Austria. 2–5 November 2017. - Fritschiana (Graz) 85: 32–34. - ISSN 1024-0306.

Regulatory evolution is important for adaptive evolution and the emergence of novelties, in part because regulatory mutations tend to be less pleiotropic than changes in exons. The functional properties of regulatory elements, e.g. short, degenerate motifs, for multiple activators and repressors, dictate the evolution of regulatory DNA (Wray et al. 2003). Stabilizing selection on transcription may explain the evolutionary turnover of transcription factor binding sites (TFBS) in enhancers (Ludwig et al. 2000). Genes have been recruited for multiple functions during evolution, by a process called transcriptional co-option (TC) (True and Carroll 2002). In TC a mutation in a gene (here called focal gene), not previously expressed in a specific tissue or cell population during development, turns the gene on in that tissue and the responsible allele is fixed in the population. As new TFBS arise easily via mutation, it was proposed that any transcription factor can co-opt (influence the transcription of) any gene in the genome (Prud’homme et al 2007). Here we define the opposite scenario, evolution by transcriptional decay (TD). In TD, a mutation reducing strongly the transcription of a focal gene in tissue or developmentally specific fashion is fixed by positive selection. An example of TC would be the recruitment of various crystallins to the vertebrate lens (Piatigorsky 2006), and of TD the loss of Pitx1 expression in pelvic structures in stickleback (Shapiro et al. 2004). Here we will use transcriptional decay and co-option as a prism to explore the principles of regulatory evolution.

 

TC or TD can arise by mutations in either trans-factors (TF) or cis-elements (figure part A). While we focus on mutations in cis, changes in the structure or tissue specific concentration of a TF can affect expression of a focal gene. Such changes are expected to be pleiotropic, with changes in expression of targets of that TF (if changes are in TF level, then the effects will be more circumscribed). Changes at the level of cis-elements will be less pleiotropic. Disruption of TFBS can for example either increase or decrease expression of the focal gene, depending on whether the TF that binds that TFBS represses or activates transcription. The complementary argument applies for mutations that generate TFBS; TC can occur by gain of an activator binding site affecting the focal gene. And in TD a gain of a binding site for repressor near the focal gene.

Regulatory mutations can be pleiotropic. In one scenario, a mutation alters the expression of two or more genes in the same chromosome region. If the fitness increase of the increased expression of the focal gene outweighs the fitness reduction of its chromosome neighbors (figure, part B), then TC can occur. The stronger the selection, the more serious the regulatory side effects can be. After fixation of such a mutation, we anticipate rounds of refinement where the deleterious expression of nearby genes will be alleviated, e.g. by loss of activator sites or gain of repressor sites (figure, part B). Other regulatory changes (miRNA binding sites, RNA degradation etc) may play a role, and the complementary case when reduced expression of two or more genes is favored will adhere to the same principles. Similar mechanistic and evolutionary logic will also be apply if adaptive expression increase of a focal gene in a tissue, leads to increased expression of the gene in other tissues.

The central principles discussed here are, i) mutations disrupting TFBS can lead to beneficial changes in gene expression, ii) cis-regulatory mutations can be pleiotropic, affecting multiple genes and potentially tissues, iii) the likelihood of fixation of such pleiotropic mutations depends on the strength of selection, iv) natural selection is likely to alleviate such side-effects by favoring modifiers (e.g. in cis or trans). Finally, these principles are likely to apply more generally, to gain and decay of associations between trans-regulators and regulatory motifs in DNA, RNA and proteins. For instance regulatory systems like those controlling mRNA splicing, export, stability and localization, translation, protein maturation and modifications and other cellular regulatory cascades.

Acknowledgements. We thank Silke Werth and other organizers of the Lichen Genomics Workshop.

References

Wray G.A., Hahn M.W., Abouheif E., Balhoff J.P., Pizer M., Rockman M.V., Romano L.A. 2003: The evolution of transcriptional regulation in eukaryotes. Molecular Biology and Evolution.20: 1377-1419.

Ludwig M.Z., Bergman C., Patel N.H., Kreitman M. 2000: Evidence for stabilizing selection in a eukaryotic enhancer element. Nature. 403: 564-567.

True J.R., Carroll S.B. 2002 Gene co-option in physiological and morphological evolution. Annual Review Cellular and Developmental Biology. 18: 53-80.

Prud'homme B., Gompel N., Carroll S.B. 2007 Emerging principles of regulatory evolution. Proceedings of the National Academy of Sciences U S A. 15: 8605-8612.

Piatigorsky J. 2006 Evolutionary genetics: seeing the light: the role of inherited developmental cascades in the origins of vertebrate lenses and their crystallins. Heredity. 96: 275-277.

Shapiro M.D., Marks M.E., Peichel C.L., Blackman B.K., Nereng K.S., Jónsson B., Schluter D., Kingsley D.M. 2004 Genetic and developmental basis of evolutionary pelvic reduction in threespine sticklebacks. Nature. 428: 717-723

Nordic Committee on Bioethics Conference: Facing Death - End of life decisions

Arnar Pálsson, 15/08/2017

Nordic Committee on Bioethics Conference: Facing Death - End of life decisions

Should end of life care for incurable ill patients include the possibility of euthanasia or physician-assisted suicide? Assisted death or euthanasia are not allowed in any of the Nordic countries, however, surveys show that an increased proportion of the public supports this.

The Nordic committee on bioethics will host a conference on address how the Nordic countries can learn from the experience on assisted death in Europe and North America. The conference aims to reach medical professionals, policy makers and academics, and will be organised in cooperation with the Centre for Ethics at the University of Iceland. The conference will take place at the University of Iceland, Veröld, hús Vigdísar, Brynjólfsgata 1, Reykjavík (main auditorium).

Full schedule and registration info.

The University of Iceland individual evaluation system

Arnar Pálsson, 09/11/2016

In this summary I would like to raise a few objections about the evaluation system that has been in use at the University of Iceland for a few decades now. The objections fall into four main categories. First are concerns about the role and output of Universities. Second is the problem of trying to measure the unmeasureable. Third is the increased corporatization of western universities and the fourth concerns the specifics of the Icelandic evaluation system. My conclusion is that the evaluation system used at the University of Iceland is fundamentally broken, should be disbanded and a new structure put in place to evaluate the performance of the teachers/researchers at the University.

I. Roles of Universities.

First I would like to highlight the roles of Universities in the modern age. Scholars, like our former rector Pall Skulason, have categorized three major roles for Universities. Skulason identifies the French (Napoleonic) university, a utilitarian institution aimed at serving the nation, solving problems at hand (concerning health, agriculture, industry, army) – often with top down administration, the German (Humboltian) university which is concerned with gathering knowledge for its own sake – letting basic research run free so to speak – obviously with the scholars them selves in charge of administration, and the English (Newtonian) university, aimed at providing the government with skilled personel to run an empire (administrators, officers, priests, lawyers, bankers etc) – the board of these universities obviously respond to the needs of governments.

Continue reading 'The University of Iceland individual evaluation system'»

NCBio meeting on genetic modification of human embryos

Arnar Pálsson, 16/06/2016

Nordic committee on bioethics in junction with the Norwegian biotechnology board, organized a miniconference on the new Crispr/Cas technology and the genetic modification of human embryos. The conference was held at the University of Oslo, June 2nd. The title was Gene therapy and human germline editing: new opportunities, new challenges.

We heared great talks by Fredrick Lanner, Gunnar Kvalheim, Johanna Ahola-Launonen, Jacob Wang, Anne-Marie Gerdes and Nils-Eric Sahlin, and were then given the task to summarize the meeting.

I will not attempt to do that here, because my notes were incomplete and the things I said didnt quite follow the notes (either a plus or minus, Im not sure).

The new technologies open some new opportunities, for studying the effects of mutations and systems on human cells and early development. There is also the future possibility of using this technology to modify the human cells, to correct serious errors in DNA to treat (somatic) or to prevent (germline) devastating diseases. The current seems to be flowing in that direction, granting of course that the technology will become efficient enough and side effects can be minimized. In fact this is the first moment that I felt that steps towards germline could and perhaps should be taken.

To counter, there were several issues raised with further developing the technology for modifying human embryos, including the slippery-slope argument, side-effects, dont-mess-with-nature, and a few others. But in general they are no unique to this technology.

The only new concept is that we may alter the genetic makeup of our species directly with this new technology. But in fact we have been changing our genetic makeup, indirectly with choices in lifestyle and human history and technological development.

In sum, I learned a lot but am still confused about the subject.

Those who want to read more should check out a new statement and report by the Danish council on ethics which summarized these issues quite well.

Statement from the Danish Council on Ethics on genetic modification of future humans (2016)

 

 

 

(Icelandic) Katrín Halldórsdóttir varði ritgerð sína

Arnar Pálsson, 30/05/2016

Sorry, this entry is only available in Icelandic.