Format: ORAL

M. Teresa Boquete1, Jess R. Aboal1, Bodil Cronholm2, Per G.P. Ericson2, J. ngel Fernndez1, Lars Hedens3, Martin Irestedt2, Johan Nylander2, Irene Bisang3

1 CRETUS, Ecology Unit, Department of Functional Biology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain 2 Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden 3 Department of Botany, Swedish Museum of Natural History, Stockholm, Sweden

Reproductive mode, sexual vs. asexual, determines the capacity of plants to disperse, shaping both their geographic distribution patterns and their population genetic makeup. All bryophytes have a high capacity to reproduce asexually which contributes to population maintenance, expansion at relatively short spatial scales, and retains extant genetic variation. The capacity to reproduce sexually, however, strongly depends on the sexual system. Sexual reproduction is common in bisexual species, but far less so in unisexual species. Thus, unisexual bryophytes are expected to show limited long-distance dispersal capacities and lower population genetic variation than bisexual species. Still, many unisexual bryophytes show remarkably wide distribution ranges. To date, we know little about the processes underlying such wide distribution ranges and the levels of population genetic variation and genetic structure at these spatial scales in unisexual bryophytes. Here, we study population genomics and its relation to reproductive patterns in the cosmopolitan, unisexual moss Pseudoscleropodium purum to contribute to filling this knowledge gap. We performed whole genome sequencing on 500 individual plants from 37 mainland and island populations across its native distribution range in Europe. With this unprecedented dataset (currently being generated), we will characterize the species large-scale spatial genetic structure and levels of genetic variation. Also, we will reconstruct its biogeographic history to infer the relative contribution of sexual and asexual reproduction to colonization processes in this species. Provided that P. purum predominantly reproduces asexually through fragmentation and clonal growth, we hypothesize that its populations will exhibit low levels of genetic variation and that genetic differentiation will increase with increasing geographic distance between populations, following an isolation-by-distance model. We further predict that the biogeographic history of P. purum will conform to a stepping-stone colonization model where the geographic range expansion was dominated by numerous short-distance dispersion events.