o:3399 Genomics reveals broad hybridization in deeply divergent Palearctic grass and water snakes (Natrix spp.) en Understanding speciation is one of the cornerstones of biological diversity research. Currently, speciation is often understood as a continuous process of divergence that continues until genetic or other incompatibilities minimize or prevent interbreeding. The Palearctic snake genus Natrix is an ideal group to study speciation, as it comprises taxa representing distinct stages of the speciation process, ranging from widely interbreeding parapatric taxa through parapatric species with very limited gene flow in narrow hybrid zones to widely sympatric species. To understand the evolution of reproductive isolation through time, we have sequenced the genomes of all five species within this genus and two additional subspecies. We used both long-read and short-read methods to sequence and de-novo-assemble two high-quality genomes (Natrix h. helvetica, Natrix n. natrix) to their 1.7 Gb length with a contig N50 of 4.6 Mbp and 1.5 Mbp, respectively, and used these as references to assemble the remaining short-read-based genomes. Our phylogenomic analyses yielded a well-supported dated phylogeny and evidence for a surprisingly complex history of interspecific gene flow, including between widely sympatric species. Furthermore, evidence for gene flow was also found for currently allopatric species pairs. Genetic exchange among these well-defined, distinct, and several million-year-old reptile species emphasizes that speciation and maintenance of species distinctness can occur despite continued genetic exchange. De-Novo Identification; Read Alignment; N.-Natrix; Gene Flow; Phylogeography; Taxonomy; Astreptophora; Speciation; Helvetica; Serpentes 1552099 10.1016/j.ympev.2023.107787 2024-08-20T08:48:12.080Z 44 yes 46 Yannis Schöneberg Senckenberg Biodiversity and Climate Research Centre / Goethe University Frankfurt Sven Winter University of Veterinary Medicine Vienna / Senckenberg Biodiversity and Climate Research Centre person 0000-0002-1890-0977 Oscar Arribas IES Castilla person Matteo Riccardo Di Nicola IRCCS Ospedale San Raffaele person Maya Master Bangor University person John Benjamin Owens Bangor University person Michail Rovatsos Charles University person Wolfgang Wüster Bangor University person Axel Janke Senckenberg Biodiversity and Climate Research Centre / Goethe University Frankfurt / LOEWE Centre for Translational Biodiversity Genomics person Uwe Fritz Senckenberg Natural History Collections Dresden person application/pdf 5260977 https://phaidra.vetmeduni.ac.at/o:3399 no yes 18 70 1552253 Molecular Phylogenetics and Evolution 9 184 Elsevier 2023