Different patterns of introgression in a three species hybrid zone among European cave salamanders

A previously undocumented three-species hybrid zone among European cave salamanders (Plethodontid) has been identified in the Northern Apennines, involving Speleomantes strinatii, S. ambrosii, and S. italicus. This discovery expands the known distribution of these species by 21 new sites and reveals complex introgression patterns, with asymmetric genetic exchange favoring S. italicus mitogenome in hybrids. The study employed mitochondrial (Cytb, ND2) and nuclear markers (NCX1 SNPs) to uncover strong mitonuclear discordance, where mitochondrial genes show geographic structure while nuclear alleles coexist across species boundaries. This finding suggests that behavioral, genetic, and ecological factors collectively influence hybridization dynamics in this unique system.

Bruni, G., Chiocchio, A., Nascetti, G., & Cimmaruta, R. (2023). Different patterns of introgression in a three species hybrid zone among European cave salamanders. Ecology and Evolution, 13(8). Portico. https://doi.org/10.1002/ece3.10437