TY  - JOUR
A1  - Schöneberg, Yannis
A1  - Winter, Sven
A1  - Arribas, Oscar
A1  - Di Nicola, Matteo Riccardo
A1  - Master, Maya
A1  - Owens, John Benjamin
A1  - Rovatsos, Michail
A1  - Wüster, Wolfgang
A1  - Janke, Axel
A1  - Fritz, Uwe
T1  - Genomics reveals broad hybridization in deeply divergent Palearctic grass and water snakes (Natrix spp.)
T2  - Molecular phylogenetics and evolution
N2  - Highlights
• Genomes for all five Natrix species, two represented by two distinct subspecies each, were sequenced.
• Two genomes were de-novo assembled to their 1.7 Gb length with a contig N50 of 4.6 Mbp and 1.5 Mbp.
• Evidence for interspecific hybridization, both between allopatric and widely sympatric species.
• Fossil-calibrated molecular clock using genomes indicates that species are ancient several million-year-old lineages.
• Our findings imply that speciation took place despite continued gene flow.
Abstract
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.
KW  - Genomics
KW  - Hybridization
KW  - Molecular clock
KW  - Natricidae
KW  - Reptilia
KW  - Speciation
KW  - Squamata
Y1  - 2023
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/78967
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-789676
SN  - 1055-7903
VL  - 184
IS  - 107787
PB  - Elsevier
CY  - Amsterdam
ER  -