{"publication_status":"epub_ahead","oa_version":"Published Version","article_number":"e70025","quality_controlled":"1","scopus_import":"1","publisher":"Wiley","PlanS_conform":"1","title":"Phenotypic divergence and genomic architecture between parallel ecotypes at two different points on the speciation continuum in a marine snail","publication_identifier":{"issn":["0962-1083"],"eissn":["1365-294X"]},"type":"journal_article","date_published":"2025-07-28T00:00:00Z","publication":"Molecular Ecology","date_created":"2025-08-03T22:01:31Z","date_updated":"2025-08-04T06:45:58Z","day":"28","department":[{"_id":"NiBa"}],"article_type":"original","citation":{"ama":"Raffini F, De Jode A, Johannesson K, et al. Phenotypic divergence and genomic architecture between parallel ecotypes at two different points on the speciation continuum in a marine snail. <i>Molecular Ecology</i>. 2025. doi:<a href=\"https://doi.org/10.1111/mec.70025\">10.1111/mec.70025</a>","apa":"Raffini, F., De Jode, A., Johannesson, K., Faria, R., Zagrodzka, Z. B., Westram, A. M., … Butlin, R. K. (2025). Phenotypic divergence and genomic architecture between parallel ecotypes at two different points on the speciation continuum in a marine snail. <i>Molecular Ecology</i>. Wiley. <a href=\"https://doi.org/10.1111/mec.70025\">https://doi.org/10.1111/mec.70025</a>","chicago":"Raffini, Francesca, Aurélien De Jode, Kerstin Johannesson, Rui Faria, Zuzanna B. Zagrodzka, Anja M Westram, Juan Galindo, Emilio Rolán-Alvarez, and Roger K. Butlin. “Phenotypic Divergence and Genomic Architecture between Parallel Ecotypes at Two Different Points on the Speciation Continuum in a Marine Snail.” <i>Molecular Ecology</i>. Wiley, 2025. <a href=\"https://doi.org/10.1111/mec.70025\">https://doi.org/10.1111/mec.70025</a>.","short":"F. Raffini, A. De Jode, K. Johannesson, R. Faria, Z.B. Zagrodzka, A.M. Westram, J. Galindo, E. Rolán-Alvarez, R.K. Butlin, Molecular Ecology (2025).","ieee":"F. Raffini <i>et al.</i>, “Phenotypic divergence and genomic architecture between parallel ecotypes at two different points on the speciation continuum in a marine snail,” <i>Molecular Ecology</i>. Wiley, 2025.","ista":"Raffini F, De Jode A, Johannesson K, Faria R, Zagrodzka ZB, Westram AM, Galindo J, Rolán-Alvarez E, Butlin RK. 2025. Phenotypic divergence and genomic architecture between parallel ecotypes at two different points on the speciation continuum in a marine snail. Molecular Ecology., e70025.","mla":"Raffini, Francesca, et al. “Phenotypic Divergence and Genomic Architecture between Parallel Ecotypes at Two Different Points on the Speciation Continuum in a Marine Snail.” <i>Molecular Ecology</i>, e70025, Wiley, 2025, doi:<a href=\"https://doi.org/10.1111/mec.70025\">10.1111/mec.70025</a>."},"author":[{"full_name":"Raffini, Francesca","last_name":"Raffini","first_name":"Francesca"},{"first_name":"Aurélien","last_name":"De Jode","full_name":"De Jode, Aurélien"},{"first_name":"Kerstin","last_name":"Johannesson","full_name":"Johannesson, Kerstin"},{"first_name":"Rui","full_name":"Faria, Rui","last_name":"Faria"},{"first_name":"Zuzanna B.","last_name":"Zagrodzka","full_name":"Zagrodzka, Zuzanna B."},{"orcid":"0000-0003-1050-4969","full_name":"Westram, Anja M","last_name":"Westram","first_name":"Anja M","id":"3C147470-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Juan","full_name":"Galindo, Juan","last_name":"Galindo"},{"full_name":"Rolán-Alvarez, Emilio","last_name":"Rolán-Alvarez","first_name":"Emilio"},{"first_name":"Roger K.","full_name":"Butlin, Roger K.","last_name":"Butlin"}],"OA_type":"hybrid","article_processing_charge":"Yes (in subscription journal)","main_file_link":[{"url":"https://doi.org/10.1111/mec.70025","open_access":"1"}],"oa":1,"language":[{"iso":"eng"}],"OA_place":"publisher","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","status":"public","abstract":[{"lang":"eng","text":"Speciation is rarely observable directly. A way forward is to compare pairs of ecotypes that evolved in parallel in similar contexts but have reached different degrees of reproductive isolation. Such comparisons are possible in the marine snail Littorina saxatilis by contrasting barriers to gene flow between parallel ecotypes in Spain and Sweden. In both countries, divergent ecotypes have evolved to withstand either crab predation or wave action. Here, we explore transects spanning contact zones between the Crab and the Wave ecotypes using low-coverage whole-genome sequencing, morphological and behavioural traits. Despite parallel phenotypic divergence, distinct patterns of differentiation between the ecotypes emerged: a continuous cline in Sweden indicating a weak barrier to gene flow, but two highly genetically and phenotypically divergent, and partly spatially overlapping clusters in Spain suggesting a much stronger barrier to gene flow. The absence of Spanish early-generation hybrids supported strong isolation, but a low level of gene flow is evident from molecular data. In both countries, highly differentiated loci were located in both shared and country-specific chromosomal inversions but were also present in collinear regions. Despite being considered the same species and showing similar levels of phenotypic divergence, the Spanish ecotypes are much closer to full reproductive isolation than the Swedish ones. Barriers to gene flow of very different strengths between ecotypes within the same species might be explained by dissimilarities in the spatial arrangement of habitats, the selection gradients or the ages of the systems."}],"doi":"10.1111/mec.70025","year":"2025","month":"07","_id":"20102","acknowledgement":"This study was supported by European Research Council grant 693030-BARRIERS to RKB; the Swedish Research Council (grant number 2021-04191) to KJ; the Portuguese Foundation for Science and Technology (FCT: 2020.00275.CEECIND and PTDC/BIA-EVL/1614/2021) to RF; grant PID2022-137935NB-I00 by MICIU/AEI/ 10.13039/501100011033/and ERDF/EU (ED431C 2020-05) to JG, grant PID2021-124930NB-I00 funded by MICIU/AEI/ 10.13039/501100011033/and ERDF/EU to ERA, Xunta de Galicia (ED431C 2024/22), Centro singular de Investigación de Galicia accreditation 2024-2027 (ED431G 2023/07), ‘ERDF A way of making Europe’ and Norwegian Research Council RCN, project 315287 to AMW."}