Kerstin Johannesson


Department of Marine
Visiting address
Tjärnö marina laboratorium, Laboratorievägen 10
45296 Strömstad
Postal address
Tjärnö marina laboratorium
45296 Strömstad

About Kerstin Johannesson

Professor in Marine Ecology and Director of Tjärnö Marine Laboratory.

Visiting address:

Department of Marine Sciences, Tjärnö Marine Laboratory, Strömstad

Research Interests

My professional interest is evolution and the mechanisms generating locally adapted populations, ecotypes and species. A main focus in my research is the study of adaptation over environmental gradients and the evolution of barriers to gene flow under divergent selection.

In my studies I use marine organisms, such as snails of the genus Littorina (periwinkles) and seaweeds of the genus Fucus (wrack). In collaboration with colleagues, I apply genetic and genomic tools, field and laboratory experiments, and modelling.

Research Activities

CeMEB - The Linnaeus Centre for Marine Evolutionary Biology

A ten-year research centre initiated by me and funded by the research councils VR and Formas during 2008-2019. Currently the centre is run as a network with minor funding from the university. The centre has provided 8 new reference genomes and more than 500 publications on marine evolutionary biology.

Please visit

Evolution and speciation in marine snails (Littorina)

1980- ongoing Originally, my graduate student project, but today a large collaborative research project on the evolutionary ecology, genetics and genomics of Littorina saxatilis and L. fabalis. With a draft genome, a gene map and large numbers of resequenced snails, we explore parallel ecotype formation and genetic clines formed over hybrid zones in these snails. A new and interesting finding is that much of the divergence between ecotypes is hosted by several inversions. All this work is done in close collaboration with Roger Butlin, Anja Westram, Rui Faria, Marina Rafajlovic and many others.

Funding: Swedish Research Council VR (since 1987).

Evolution and conservation genetics of brown seaweed (Fucus)

2004-ongoing This project was initiated to address the taxonomic status of a dwarph morph of Baltic Sea Fucus vesiculosus. When we applied genetic analyses, the dwarf morph unveiled a separate species, Fucus radicans. This species is endemic to the Baltic Sea and a major perennial seaweed in the north. We have also discovered that a unique trait of Baltic Sea fucoids is cloning, which is important knowledge in conservation and management of these species. I run this project together with Ricardo Pereyra and in collaboration with many others.

Funding: Swedish Research Council, Formas (2004-2011), BONUS-BaltGene (2009-2011), BONUS-Bambi (2014-2017), MARFOR (2017-2019).

Earlier Research Activities

BaltGene – Baltic Sea Genetic Biodiversity

2009-2011 (KJ coordinator, 20 researchers involved from 7 universities in 4 countries) A multidisciplinary research project under the BONUS programme with focus on describing the population genetic structure of 8-10 Baltic Sea species. The program produced more than 40 scientific publications (all listed on the web page), 5 PhD thesis, and a web-tool providing guidelines for end users. Funding: BONUS EEIG, 1.6 m€

MARBIPP - Marine Biodiversity, Patterns and Processes

2001-2006 (KJ coordinator, 35 Swedish researchers involved from 5 research organizations) This was a broad research program with the objective of producing new knowledge and end-user friendly advices in the area of marine coastal biodiversity. The program dealt mainly with five coastal biotopes; seagrass beds, macroalgal forests, shallow sandy bottoms, mussel beds and deep coral reefs. The program produced more than 80 scientific publications, 9 PhD thesis (see and web-tool guidelines for end-users (see Funding: Swedish Environmental Protection Agency, 35 million SEK

EUMAR - European Marine Genetic Biodiversity

2001-2004 (KJ coordinator, 30 EU researchers involved from 5 countries) Research program addressing conservation genetics of marine invertebrate species of coastal Europe, with special emphasis on mechanisms that generated genetic structures in macro algae, seagrasses, snails, limpets, and barnacles. Collaborating partners from Italy (2 partners), Spain (1 partner), Belgium (1 partner), UK (2 partners). This program produced about 70 scientific publications and 5 PhD theses. Funding: 5th FP European Union, 1.8 million EURO.

Scientific publications

A selection of recent publications (for more recent publications download my CV)

Johannesson K, Le Moan A, Perini S, André C. A Darwinian laboratory of multiple contact zones. Trends in Ecology and Evolution

Nunez JCB, Stephen Rong S, Damian-Serrano A, Burley JT, Elyanow RG, Ferranti DA, Neil KB, Glenner H, Alm Rosenblad M, Blomberg A, Johannesson K, Rand DM. Ecological load and balancing selection in circumboreal barnacles. Molecular Biology and Evolution (in press)

Kinnby A, Jonsson PR, Ortega-Martinez O, Töpel M, Pavia H, Pereyra RT, Johannesson K. 2020. Combining an ecological experiment and a genome scan show idiosyncratic responses to salinity stress in local populations of a seaweed. Frontiers in Marine Science 7:470.

Westram AM, Faria R, Butlin RK, Johannesson K. 2020. Inversions and evolution. eLS_A29007

Morales H, Faria R, Johannesson K, Larsson T, Panova M, Westram AM, Butlin RK. 2019. Genomic architecture of parallel ecological divergence: beyond a single environmental contrast. Science Advances 5:eaav9963

Faria R, Johannesson K, Butlin RK, Westram AM. 2019. Evolving inversions. Trends in Ecology and Evolution 34:239-248. (Equal contribution all authors, KJ corresponding author.)

Faria R, Chaube P, Morales H, Larsson T, Lemmon AR, Lemmon EM, Rafajlovic M, Panova M, Ravinet M, Johannesson K, Westram AM, Butlin RK. 2019. Multiple chromosomal rearrangements in a hybrid zone between Littorina saxatilis ecotypes. Molecular Ecology 28:1375-1393.

Westram AM, Rafajlovíc M, Chaube P, Faria R, Larsson T, Panova M, Ravinet M, Blomberg A, Mehlig B, Johannesson K, Butlin R, 2018. Clines on the seashore: The genomic architecture underlying rapid divergence in the face of gene flow. Evolution Letters 2:297-309

Jonsson PR, Kotta J, Andersson HC, Herkul K, Virtanen E, Nyström Sandman A, Johannesson K, 2018. High climate velocity and population fragmentation may constrain climate-driven range shift of the key habitat former Fucus vesiculosus in the Baltic Sea. Diversity and Distribution 24:892–905

Reusch TBH, Dierking J, Andersson HC, Bonsdorff E, Carstensen J, Casini M, Czajkowski M, Hasler B, Hinsby K, Hyytiäinen K, Johannesson K, Jomaa S, Jormalainen V, Kuosa H, Kurland S, Laikre L, MacKenzie BR, Margonski P, Melzner F, Oesterwind D, Ojaveer H, Refsgaard JC, Sandström, Schwarz G, Tonderski K, Winder M, Zandersen M, 2018. The Baltic Sea as a time machine for the future coastal ocean. Science Advances 2018;4:eaar8195.

Rafajlović M, Kleinhans D, Gulliksson C, Fries J, Johansson D, Ardehed A, Sundqvist L, Pereyra RT, Mehlig B., Jonsson PR, Johannesson K, 2017. Neutral processes forming large clones during colonisation of new areas. Journal of Evolutionary Biology 30:1544-1560.

Johannesson K and Butlin R. 2017. What explains rare and conspicuous colours in a snail? - A test of time-series data against models of drift, migration or selection. Heredity 118:21–30. doi:10.1038/hdy.2016.77

Johannesson K. 2015. What can be learnt from a snail? Evolutionary Applications 9:153-165 doi: 10.1111/eva.12277

Butlin RK, Saura M, Charrier G, Jackson B, André C, Caballero A, Coyne JA, Galindo J, Grahame JW, Hollander J, Kemppainen P, Martínez-Fernández M, Panova M, Quesada H, Johannesson K, Rolán-Alvarez E. 2014. Parallel evolution of local adaptation and reproductive isolation in the face of gene flow. Evolution 68:935-949.

Johannesson K, Panova M, Kemppainen P, Rolán-Alvarez E, André C and Butlin RK 2010. Repeated evolution of reproductive isolation in a marine snail - unveiling mechanisms of speciation. Philosophical Transactions of the Royal Society B (Biology) 365:1735-1747.

Highly cited earlier publications (google scholar statistics)

Reusch TBH, Dierking J, Andersson HC, Bonsdorff E, Carstensen J, Casini M, Czajkowski M, Hasler B, Hinsby K, Hyytiäinen K, Johannesson K, Jomaa S, Jormalainen V, Kuosa H, Kurland S, Laikre L, MacKenzie BR, Margonski P, Melzner F, Oesterwind D, Ojaveer H, Refsgaard JC, Sandström, Schwarz G, Tonderski K, Winder M, Zandersen M, 2018. The Baltic Sea as a time machine for the future coastal ocean. Science Advances 4:eaar8195. (Cited 114 times)

Johannesson K & André C 2006. Life on the margin - genetic isolation and diversity loss in a peripheral marine ecosystem, the Baltic Sea. Molecular Ecology 15:2013-2029. This publication was chosen by the Faculty of 1000 Biology. (Cited 405 times)

Tatarenkov A, Bergström L, Jönsson RB, Serrao EA, Kautsky L and Johannesson K 2005. Intriguing asexual life in marginal populations of the brown seaweed Fucus vesiculosus. Molecular Ecology 14:647-651. (Cited 135 times)

Johannesson K 2001 Parallel speciation: a key to sympatric divergence. Trends in Ecology and Evolution 16:148-153 (Cited 106 times)

Johannesson K, Johannesson B & Lundgren U 1995 Strong natural selection causes microscale allozyme variation in a marine snail. Proc. Nat. Acad.Sci., USA 92:2602-2606. (Cited 153 times)

Johannesson K, Rolán-Alvarez E & Ekendahl A 1995 Incipient reproductive isolation between two sympatric morphs of the intertidal snail Littorina saxatilis. Evolution 49:1180-1190. (Cited 201 times)

Johannesson K, Johannesson B & Rolán-Alvarez E 1993 Morphological differentiation and genetic cohesiveness over a microenvironmental gradient in the marine snail Littorina saxatilis. Evolution 47:1770-1787. (Cited 222 times)

Johannesson K 1988 The paradox of Rockall: why is a brooding gastropod (Littorina saxatilis) more widespread than one having a planktonic larval dispersal stage (L. littorea)? Marine Biology 99:507-513. (Cited 339 times)

Janson K 1983 Selection and migration in two distinct phenotypes of Littorina saxatilis in Sweden. Oecologia 59:58-61. (Cited 150 times)