March 9, 2021

The paper we collaborated on, revising a textbook example of hybrid zone, made the cover of the Journal of Biogeography.

The fire- and yellow-bellied toads, Bombina bombina and B. variegata, form a famous hybrid zone in southern Poland, first described in 1976 by professor Jacek Szymura from the Jagiellonian University in Kraków. This system inspired many advances on hybrid zone and speciation research. International research team including Tomasz Suchan from our group addressed a timely reassessment of this model system using genome-wide data. The analyses showed that, on the one hand, the two species always form steep transitions in the area of a few kilometers, indicating strong reproductive isolation between the two species. On the other hand, weak allele diffusion into parental populations was evidenced. Hence, despite strong reproductive isolation, selection against hybrids is not sufficient to fully prevent diffusion of all alleles into the opposite gene pool.


Dufresnes C, Suchan T, Smirnov NA, Denoƫl M, Rosanov JM, Litvinchuk SM, 2021. Revisiting a speciation classic: Comparative analyses support sharp but leaky transitions between Bombina toads. Journal of Biogeography 48: 548-560. DOI