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  Revealing the genomic basis of reproductive mode evolution and speciation in Littorina snails

   School of Life Sciences

   Wednesday, July 31, 2024  Funded PhD Project (UK Students Only)

About the Project

We are seeking an enthusiastic and motivated PhD student to study the links between reproductive mode evolution and speciation in intertidal snails from the genus Littorina.

The process of speciation involves the build-up of isolating barriers that restrict gene exchange between populations. Although barriers to gene flow are critical to divergence and species coexistence, we rarely understand the traits and loci that underpin strong isolation.

The aim of this project is to understand how differences in female reproductive mode contribute to strong isolation between closely related species of intertidal snail. In the UK and Europe, a live-bearing species of periwinkle (Littorina saxatilis) coexists with egg-laying species (Littorina compressa and Littorina arcana). A lack of hybrids between sympatric egg-layers and live-bearers indicates that the barrier to gene flow between them is very strong.

Recent work has revealed many candidate regions of genome that underpin the difference in reproductive mode. In this project, you will use a new reference genomes, new and existing genomic data, and cutting-edge methods to determine if mode-associated loci also act as barriers to gene flow. Specific objectives include: (1) to more precisely determine the number and genomic distribution of loci associated with the difference in reproductive mode; (2) to determine if reproductive mode acts a barrier by (a) identifying barrier loci and (b) testing for overlap with reproductive mode-associated loci; and (3) to reconstruct the demographic history of divergence to reveal help us understand when and how barriers to gene flow evolved. The successful candidate will be encouraged to take the project in directions that excite them most.

You will work in the Speciation Research Group ( led by Dr Sean Stankowski in the Ecology and Evolution department at the University of Sussex, Brighton. There will be ample opportunity to collaborate and share findings with other scientists from the Littorina research community (

 Informal enquiries about the project are especially welcome and can be made to Sean Stankowski at

How to apply:

Please note that interviews will be held as applications are received. This advert will close as soon as a candidate is successfully appointed.

Please submit a formal application through the online admissions portal attaching a CV, degree transcripts and certificates, statement of interest and two academic references. No research proposal required.

On the application system select Programme of Study – PhD Biology. Please ensure you state the project title under funding obtained and include the proposed supervisor’s name where required.

Ideal candidates will have some bioinformatics skills (coding in bash, Python and or R), experience working with genomic datasets, will have used a HPC, and be excited about the subject area. Candidates should have or expect to obtain a minimum 2:1 undergraduate degree. An MSc degree will be advantageous. Your qualification should be in Biology or a related subject area. You may also be considered for the position if you have other professional qualifications or experience of equivalent standing.

Applications are particularly welcomed from candidates with protected characteristics – e.g., from Black and other ethnic minorities – who are under-represented in postgraduate research at our institution.

For enquiries about the project, please contact supervisor:

Biological Sciences (4)

Funding Notes

This fully-funded position, starting September 2024, covers Home (UK) tuition fees and a stipend at standard UKRI rates for 3.5 years. Applicants with overseas fee status need to provide evidence showing how they will fund the difference between Home and International tuition fees (approx. £18k per year).


Stankowski, S., Zagrodzka, Z. B., Garlovsky, M. D., Pal, A., Shipilina, D., Castillo, D. G., ... & Butlin, R. K. (2023). Selection on many loci drove the origin and spread of a key innovation. bioRxiv, 2023-02.
Stankowski, S., Westram, A. M., Zagrodzka, Z. B., Eyres, I., Broquet, T., Johannesson, K., & Butlin, R. K. (2020). The evolution of strong reproductive isolation between sympatric intertidal snails. Philosophical Transactions of the Royal Society B, 375(1806), 20190545.
Ravinet, M., Faria, R., Butlin, R. K., Galindo, J., Bierne, N., Rafajlović, M., ... & Westram, A. M. (2017). Interpreting the genomic landscape of speciation: a road map for finding barriers to gene flow. Journal of evolutionary biology, 30(8), 1450-1477.
Stankowski, S., & Ravinet, M. (2021). Defining the speciation continuum. Evolution, 75(6), 1256-1273.

How good is research at University of Sussex in Biological Sciences?

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