@article {S{\o}nsteb{\o}154492, author = {J{\o}rn Henrik S{\o}nsteb{\o} and Adam Vivian-Smith and Kalev Adamson and Rein Drenkhan and Halvor Solheim and Ari M. Hietala}, title = {{\textquotedblleft}Genome-wide population diversity in Hymenoscyphus fraxineus points to an eastern Russian origin of European Ash dieback{\textquotedblright}}, elocation-id = {154492}, year = {2017}, doi = {10.1101/154492}, publisher = {Cold Spring Harbor Laboratory}, abstract = {European forests are experiencing extensive invasion from the Ash pathogen Hymenoscyphus fraxineus, an ecological niche competitor to the non-pathogenic native congener H. albidus. We report the genome-wide diversity and population structure in Asia (native) and Europe (the introduced range). We show H. fraxineus underwent a dramatic bottleneck upon introduction to Europe around 30-40 generations ago, leaving a genomic signature, characterized by long segments of fixation, interspersed with {\textquotedblleft}diversity islands{\textquotedblright} that are identical throughout Europe. This means no effective secondary contact with other populations has occurred. Genome-wide variation is consistently high within sampled locations in Japan and the Russian Far East, and lack of differentiation amongst Russian locations suggests extensive gene flow, similar to Europe. A local ancestry analysis supports Russia as a more likely source population than Japan. Negligible latency, rapid host-range expansion and viability of small founding populations specify strong biosecurity forewarnings against new introductions from outside Europe.}, URL = {https://www.biorxiv.org/content/early/2017/06/23/154492}, eprint = {https://www.biorxiv.org/content/early/2017/06/23/154492.full.pdf}, journal = {bioRxiv} }