Roger Butlin

My research is concerned primarily with the origin of barriers to gene exchange, especially the evolutionary genetics of reproductive isolation. I have used insect acoustic and chemical signals as model systems to investigate the controversial process of reinforcement and genomic approaches to investigate barriers to gene flow. 

Currently, my research is focused on contact zones in Littorina to study local adaptation and the transition to speciation through the acquisition of new barriers, and the coupling of existing barriers to gene flow.

Other speciation projects include experimental evolution in monogonont rotifers to test impacts of gene flow and recombination on speciation and collaborations in projects on postmating, prezygotic isolation in Drosophila, host race formation in aphids, Howea palms and Formica ants. 

I also collaborate on the genetics and evolution of the parasitic plant Striga, the evolution of asexual reproduction using ostracods and lizards, and evolution at range margins.

Kerstin Johannesson

My interest in Littorina started with a masters project 40 years ago. These snails are fascinating and they have prompted me to ask a number of questions about evolution and ecology over the years. 

Questions such as:

In recent years increasingly powerful genomic resources have opened up ways to address fascinating questions, such as: 

João Carvalho 

I'm currently doing a PhD in Biodiversity, Genetics and Evolution at the University of Lisbon within the Evolutionary Genetics group of CE3c. During my PhD project I aim to develop and test new tools to infer past demographic events in populations. 

I'm particularly interested in the development of statistical tools, using approximate Bayesian computation (ABC) methods, that would allow us to leverage the power of pooled sequencing to perform demographic inferences. 

I plan to apply those methods to a large Littorina saxatilis dataset and contribute to our understanding of the evolutionary origins of populations adapted to particular features of the environment.

Aurélien De Jode

I am interested in biodiversity patterns and how they are influenced by environmental factors, in particular in the marine environment. 

During my PhD, my research covered two levels of biodiversity: the diversity of species in communities and the genetic diversity within species. Therefore, I used population genetic/genomics and community ecology based on genetic tools (metabarcoding). My study system was the coralligenous habitat, a benthic biogenic habitat constituting a biodiversity hotspots in the Mediterranean Sea. 

My past research also brought me to work on species delimitation using genetic data, discovery of cryptic species and on speciation. I worked with a wide variety of organisms from marine invertebrate to macroalgae and phytoplankton. 

I am currently working on speciation genomics in Littorina saxatilis, looking at the build-up of barriers to gene flow at the genomic level between the ecotypes. In all my research, I use bioinformatic tools and programming in several languages to analyse dataset obtained from different New Generation Sequencing technologies.

Martin Eriksson

I work with computer models of range expansions. In particular, I am interested in the role of phenotypic plasticity during and after range expansions. How does phenotypic plasticity affect the range expansion capacity of a population and what are the effects on the local genetic adaptation? 

The models will be connected to empirical data from organisms that have colonised the Baltic Sea since it opened to the ocean after the last glacial period.

Rui Faria 

I am an evolutionary biologist primarily focused on the study of adaptation and speciation. In particular, I'm interested in understanding the role of chromosomal rearrangements in adaptation and reproductive isolation mainly using Littorina species as model systems. 

Among these, I started by investigating the genomic architecture of parallel evolution of ecotypes within L. fabalis and of divergence between this species and L. obtusata, covering the whole speciation continuum. 

In 2016, I joined Roger Butlin's lab, where we identified multiple inversions in and assessed their role in parallel ecotype divergence, which opened new avenues of research with relevant implications in the field. 

I am now back to Portugal where I have been investigating the evolution of chromosomal inversions in L. saxatilis together with Roger Butlin and other researchers in this group and the genetic basis of colour polymorphism in L. fabalis with Miguel Carneiro at CIBIO/INBIO. My ultimate goal is to contribute to an open and creative environment while searching for answers to a diverse array of problems within the field of evolutionary biology.

Bingqian Han

I completed my MSc degree at Sun Yat-sen University, China, where I used differential gene expression analysis and pool-seq sequencing to investigate the genetic basis of heteranthery and the regulation mechanisms of floral development. 

Currently, I joined Anja Westram's group as a PhD fellow at Nord University to further explore my interests in the genomic basis and spatial patterns of local adaptation. 

My PhD project is centred on temperature adaptation in the marine snail Littorina saxatilis. We plan to combine QTL and gene expression analyses approaches to identify genomic regions associated with temperature tolerance across both shore level gradients and latitudinal gradients.

Katie Hearn

The origin of species via adaptive divergence in the face of gene flow is a controversial process, but may be aided by processes that restrict recombination in the genome. Suppression of recombination combats the homogenising effect of gene flow by maintaining coadapted complexes of alleles at locally adaptive loci and can enable the build-up of reproductive isolation. Putative chromosomal inversions discovered in Littorina saxatilis may contribute to differentiation between locally adapted populations. 

My work looks at understanding the role of genomic architecture (including the inversions), habitat choice and divergent selection on local adaptation between populations and on the speciation process. Further, a main focus of my work is how these processes interact with sex determination and the early evolution of sex chromosomes. 

One linkage group in L. saxatilis shows genetic differences (signals of inversions) between the sexes as well as between ecotypes. Due to a comparable role of recombination suppression in sex chromosome evolution to adaptive divergence - by linking sexually antagonistic loci to sex-determining loci to maintain favourable combinations - there is potential for inversions on this linkage group to play a role in both evolutionary processes. 

I aim to characterise the sex-genotype-environment associations of this putative young sex chromosome and determine how it contributes to (and is affected by) local adaptation and reproductive isolation.

Eva Koch 

I'm an evolutionary biologist and was a postdoc in Roger Butlin's group in Sheffield. A main focus of my work is local adaptation and its underlying mechanisms. 

During my PhD I used quantitative genetics, whole transcriptomes, and experimental evolution to study adaptations to new environments in flour beetles. 

In Littorina my research focuses on the effects of chromosomal inversions on phenotypes and their contribution to ecotype formation.

Luisa Kumpitsch

I am interested in sperm-egg interactions in marine external fertilisers and how these interactions are influenced by climate change effects, such as ocean acidification or temperature elevation. 

In Littorina, I want to investigate the gamete morphology in the different ecotypes and how the acrosome reaction can be induced, a process that is crucial for fertilisation and is initiated in the sperm cell when it encounters an egg.

Erica Leder

I am an evolutionary biologist with a particular interest in understanding the molecular mechanisms of phenotypic evolution. 

Using genome-wide approaches (eg proteomics, transcriptomics, whole genome sequencing), I aim to identify the molecular mechanisms responsible for variation in traits under selection. 

In Littorina, I am investigating gene regulatory networks responsible for phenotypic variation of snail ecotypes, particularly shell morphology.

Alan Le Moan 

I am generally interested in how the process of speciation is achieved, how new species evolved and what is the contribution of the environment to this process of speciation. To answer these questions, I am using mostly population genomics and comparatives approaches. 

I have been working on different marine species (tunicates and fishes) that have the particularity to show extreme value of population size and/or dispersal capacity, limiting the effect of genetic drift on the process of divergence, which makes them good model species to study the processes linked to natural selection. 

I am now working with the periwinkle Littorina fabalis to study further the process of speciation. This species of snail shows two ecotypes, a dwarf and a large ecotype, which live in sympatry along the seashore of Europe. I am trying to dissect their genome in order to characterise the regions that create barriers to reproduction between ecotypes.

Olga Ortega-Martinez

I work in Professor Johannesson's research group where I am involved in the optimisation of diverse nucleotide protocols and development of DNA libraries for different organisms under the evolutionary scope, including Littorina saxatilis and L. fabalis and Fucus vesiculosus. I am also working with the brittle star Amphiura filiformis

I have been part of developing all basic expression analysis techniques in this organism and I am now the coordinator of the genome sequencing initiative for A. filiformis as part of CeMEB at Göteborgs Universitet.

Marina Panova

I started to work with Littorina snails already during my BSc and MSc studies at St. Petersburg State University, looking at the behaviour and ecology of the snails. 

In my PhD at the University of Gothenburg I used population genetics approaches to study evolution of the Swedish Crab and Wave ecotypes, after which I gradually moved to phylogeography, gene expression, population genomics and finally, the de novo genome project for Littorina saxatilis

My main research focus is on how genes and genomes change in the process of adaptation and speciation, and what genomic features may facilitate those processes. 

At the gene level, I am looking at the evolution of a few candidate genes that are probably under strong divergent selection in the snails, such as aspartate aminotransferase in L. saxatilis and arginine kinase in L. fabalis

At the genome scale, I am working with the whole genome annotation and annotation of genes that show sequence-level and/or expression-level variation between the ecotypes. Recently, I became interested in metabarcoding, metagenomics and eDNA approaches. 

In connection to Littorina, I am conducting a project on microbiomes associated with the snail ecotypes.

Marina Rafajlovic

I am mostly interested in the mechanisms of speciation, evolution of species' ranges and the evolutionary (dis)advantages of sexual reproduction. I do not list these as three separate topics in evolution - simply because they are all highly entangled. 

In connection to this, I've been asked several times: "Which of these three topics is your favourite?", and I would usually reply with: "Which three topics? I mentioned only one." 

Having a background in Physics, my research method involves mathematical modelling and individual-based computer simulations informed by, and/or tested by empirical genetic data. The models I use are either general and conceptual, or specifically tailored to account for life-history characteristics of a species of interest. 

The particular species for which I have been developing models so far include, among others, the marine snail, Littorina saxatilis, brown macroalgae Fucus radicans and Fucus vesiculosus, isopod Idotea balthica, as well as humans. 

An important component of my research is tight collaboration with many excellent empiricists, bioinformaticians and theoretical biologists (not least within the "Littorina group"). Many of the collaborations I have today were established through the Centre of Marine Evolutionary Biology (CEMEB)

Photo: Hasselblad Foundation.

Francesca Raffini

I am broadly interested in natural sciences, particularly biology and understanding the amazing diversity we can observe in Nature. My research experience has revolved around understanding how biological and environmental processes within and among populations or species produce biodiversity and adaptations, and how to preserve them. 

As a former postdoc at the University of Sheffield (UK), I have focused on adaptation and speciation, key processes that determine biological diversity and its distribution in space and time. Speciation requires the evolution of barriers to gene flow between diverging populations. The mechanisms underlying these processes are often unclear, particularly when they occur under gene flow. I am currently focusing on Littorina saxatilis, an ideal study system to address this conundrum. 

This marine snail shows repeated adaptive divergence between two ecotypes associated with different rocky shore habitats: "crab", inhabiting boulder fields exposed to crab predation, and "wave", living on cliffs subjected to dislocation by wave. They are morphologically and behaviourally distinct and adapted to their specific micro-environment (crab/wave exposure), but hybridise where the two habitats overlap. 

Hybrid zones are particularly useful to identify genomic loci under selection, clarify the relationship between phenotype, genotype, environment and fitness, and the mechanisms underlying (adaptive) divergence. These findings shed light on the factors and interactions that promote speciation-with-gene-flow in nature. 

Additionally, understanding what determines range expansion or extinction is crucial to predict the success of biological invaders. We have tackled this long-standing question from an unparalleled perspective using the failed expansions in Littorina saxatilis, a very successful Atlantic coloniser and the earliest confirmed alien species in the Mediterranean Sea, where, however, it failed to thrive despite its high dispersal ability and adaptability. 

Now I am exploring different shores at the Stazione Zoologica Anton Dohrn (Naples, Italy), but I continue to collaborate on Littorina projects.

James Reeve

I am researching chromosomal inversions in Littorina saxatilis to shed more light on their origins and function.

My research is divided into three main projects:

Sean R Stankowski

I am broadly interested in speciation—the evolution of reproductive isolation between populations. 

Reproductive isolation (RI) is critical to the origin and maintenance of biodiversity because it allows organisms to adapt to different ecological niches while living together in the same areas. Despite being a major focus of research since Darwin, there is still much to learn about how and why speciation happens. 

Some key questions that I address include: 

I address these questions using a range of tools including classical genetics, cutting edge genomics and field and laboratory experiments.

Anja M Westram 

I am an evolutionary biologist studying processes generating biological diversity - adaptation and speciation - and particularly their genomic basis and spatial patterns. For that, I combine field surveys, morphological and behavioural phenotyping, and analyses of various genomic data sets. I use Littorina saxatilis as a model system. 

In particular, I am interested in parallel evolution - a process where the same trait evolves repeatedly in the same direction in independent populations. L. saxatilis is ideal for studying this process, as numerous parallel hybrid zones exist across Europe. I look at parallel divergence of the Crab and Wave ecotypes as well as at parallel adaptation to repeated temperature gradients. 

In addition, I am interested in the genomic architectures facilitating (parallel) adaptation, studying eg the role of chromosomal inversions. I combine my empirical studies with conceptual work and simulations to understand evolutionary processes and open questions and problems in the field of evolutionary biology more generally.

Le Qin Choo

I am interested in the process of speciation and how the changes in the environment affect it. For my PhD project, I studied the genome-wide divergence in the pteropod Limacina bulimoides. Pteropods are marine planktonic snails that are known as bioindicators of ocean acidification due to their thin shells that are susceptible to dissolution.

 In my present role as a postdoc in Sheffield, I am investigating the origin and role of chromosomal inversions across Littorina species with haplotagging, which allows haplotype information to be reconstructed from linked-read data, to improve the accuracy of detection of the breakpoints in these structural rearrangements. With this information, we can test if inversions can be used repeatedly across ecotypes and species and facilitate divergent adaptation.

Diego Fernando Garcia Castillo

I finished my master's degree in Bioinformatics at the Chinese Academy of Agricultural Sciences in 2020. My master's thesis consisted of the development of a genomic database for the common wheat and its ancestors that we called WheatGene.

Currently, I am doing my PhD at the Institute of Science and Technology Austria, affiliated with the research group on Evolutionary Genetics of professor Nick Barton. In my doctoral research, I am studying the genetic basis of rapid local adaptation of the marine snail Littorina saxatilis. I am using anthropogenically introduced populations of L. saxatilis to investigate the genetic mechanisms that allow a population to adapt to the local environment in the short term. I seek to answer fundamental questions like how is adaptive variation distributed in the genome, whether is adaptation based on a few or many loci, what is the contribution of different types of genetic variants, and what is the contribution of standing genetic variation and migration.

Amin Ghane

I did an Erasmus Mundus joint master's degree in Marine Environment and Resources (MER+). During my master’s thesis project, I utilised various genomic analyses to find the sex-associated genomic variation in Crab and Wave ecotypes of Littorina saxatilis on the Swedish west coast. 

As an intern at the Institute of Science and Technology (IST), by analysing SNP data, I am investigating the difference in sex determination systems between the two ecotypes of L. saxatilis

Pierre Barry 

I am an evolutionary biologist interested in understanding the selective and demographic mechanisms that drive the establishment of reproductive isolation barriers that lead to speciation in natural populations mainly using fieldwork sampling and analyses of genomic DNA  sequences.  


I completed a PhD at the University of Montpellier, where I studied the role of life-history traits on the etablishment of reproductive isolation, by comparing speciation history of 20 marine fish species having a similar Atlantic Ocean - Mediterranean Sea genetic divergence, similar genome architecture and various life-history traits. 


As a postdoctoral researcher at the CIBIO/INBIO in Porto, I am working on the inference of selective and demographic history of inversions that segregated within the Crab and Wave ecotypes of Littorina saxatilis and their impact on phenotypic divergence and reinforcement to understand their role on the establishment of reproductive isolation between Littorina saxatilis ecotypes

Alfonso Balmori de la Puente

I am a biologist interested in the study of the evolutionary, genetic and ecological mechanisms that influence the conservation of animal species and populations.


I have been working in the group of Dr. Jose Castresana (Institute of Evolutionary Biology UPF-CSIC, Barcelona, Spain) during the PhD and first postdoc, using an integrative toolkit that includes laboratory protocols to prepare genomic libraries of non-invasive samples of mammals; as well as bioinformatic tools to asses population structure, estimate divergence times using coalescent models and perform individual monitoring through relatedness and inbreeding coefficients.


During my next postdoc, I will be joining the group of Dr. Rui Faria at CIBIO (Research Centre in Biodiversity and Genetic Resources, University of Porto, Portugal) for one year. With Rui, I am planning to expand my research areas and learn about genomics of adaptation and the impact of chromosome inversions in the evolution of marine snails populations of the genus Littorina, and possibly the study of host-parasite interactions; as well as contribute with my experience in the progress of the group.

Juan Galindo

I am interested in biodiversity of marine gastropods (Littorina spp., Nucella spp.) from the point of view of adaptation and speciation. I study these processes through ecological, behavioural, physiological and genomic studies. My main focus is the study of populations/ecotypes from Galician shores (NW Iberian Peninsula), a known glacial refugia for marine organisms. Understanding how reproductive barriers or barriers to gene flow evolve from an ecological, behavioural, physiological, and phenotypic perspective and what is the genetic basis and genomic architecture of those encompasses most of my research.

I am also interested in the study of colour polymorphism in these marine gastropods, the mechanisms responsible for its maintenance and the genetic basis of the different colours.

Former members

André Pires

I finished my bachelor degree in Bioengineering with specialisation in Biomedical engineering in 2020 at Universidade Católica do Porto - Escola Superior de Bioengenharia. I am currently in the second year of my masters in Bioinformatics and Computational Biology, at the Faculty of Sciences at the University of Porto, Portugal. 

My Msc thesis project is about shell shape evolution of the marine gastropod Littorina obtusata across an environmental gradient at high latitudes, under the supervision of Rui Faria at CIBIO. I am particularly interested on phylogenetic reconstruction and understanding the processes shaping evolution using genomic data.

Jenny Larsson 

I am a final year PhD student in Roger Butlin's group at the University of Sheffield. My background is in mathematics, where my main interests are in the areas of shape and geometry, and I am now applying my mathematical knowledge to biology by analysing the shell shape variability in Littorina saxatilis

My research includes developing a method for quantifying shape and describing the growth pattern of mollusc shells, and constructing 3D models, from 2D images. This developmentally-informative description can then be used to analyse shape variation of large sample sets, not only for L. saxatilis but within and between a wide variety of species, and is hoped to improve our ability to understand the genetic basis of shell shape. 

I am currently also working on fluid dynamics analysis of various shapes and sizes of L. saxatilis shells to better understand their different hydrodynamic properties, which relates to their fitness in wave swept environments.

Suda Parimala Ravindran

I am interested in understanding how snails adapt to contrasting habitats on the Swedish coast. For this, I use population genomics approaches to identify candidate genes that shape local adaptation at both regulatory and sequence level.

Hernan Morales

I am an evolutionary biologist primarily focused on the study of adaptation, speciation and conservation. My main research interest revolves around how genetic diversity is generated, maintained and lost. 

I was involved in the population genomics analyses of hundreds of genomes to shed light on how Littorina adapted multiple times to replicated heterogenous environments. 

As I continue to collaborate with the Littorina team, I am currently a Research Fellow at the Evogenomics section of Copenhagen University trying to figure out how endangered birds species have lost genetic diversity in the last few hundred years using historical and modern genomes.

Meghan L Wharton

I am broadly interested in evolutionary theory and behavioural ecology of marine animals, in particular sensory ecology and its links to behaviour. 

As a research technician in the Butlin group, I have been largely involved in fieldwork carried out on the rocky shore on the Galician coast. This work is aimed at testing hypotheses about how local adaptation and habitat choice contribute to speciation between the crab and wave ecotypes of the rough periwinkle Littorina saxatilis. These ecotypes are associated with distinct microenvironments in the intertidal zone and are thought to hybridise within the middle shore. 

I am currently involved in analysing data from mark-recapture experiments to characterise patterns of movement after relocation (ie up-shore, down-shore), and to test if habitat choice may contribute to reproductive isolation.

Zuzanna B Zagrodzka

I have been part of the Littorina group since 2015 - at the beginning working as a research technician for several months at the Tjärnö Marine Research Station and now for the last three years in Sheffield. Most of my time I am responsible for planning and organising laboratory work and fieldwork. 

Recently, I have started to analyse RNAseq data to identify female reproductive genes or differentially expressed regions which contribute to reproductive isolation between Littorina saxatilis and Littorina arcana. I am always keen to learn and try new protocols and learn new skills.

Ana Peris

My general research interest is genetic and ecological responses to different environments. I am especially interested in studying evolutionary processes, phenotypic plasticity, local adaptation and speciation. 

During my PhD, I studied the ecological and genetic variation of Arctic charr (Salvelinus alpinus) morphs, which can live in different habitats in a lake. 

I am currently working as a postdoctoral researcher at Nord University as a part of the Landscape Genomics Group. I am studying the genomic basis of temperature adaptation in ecotypes of the marine snail (Littorina saxatilis) in different geographical locations. Genomic and experimental approaches will be combined to study temperature adaptation of L. saxatilis.