Format: ORAL

Stella Huynh1

1 Institute of Research for Development, Montpellier, France

Polyploidization, or whole-genome doubling, appears to be widespread across plants, particularly in angiosperms. However, it is known to induce sudden drastic changes in nascent polyploid species at both genomic and physiological levels. Allopolyploidy combines polyploidization and hybridization, which additionally causes epigenetic instabilities between genetically divergent maternal and paternal subgenomes that trigger bursts of transposable elements. Nevertheless, allopolyploid species are frequent and generally have a larger geographical distribution than their diploid progenitors. This suggests that successful species might have evolved evolutionary advantages pertaining to their allopolyploid state. To investigate the long-term impact of allopolyploidy on species evolution and adaptation, we used the wild wheat Aegilops L. species as model species, a well-known diploid-allopolyploid system in which half of the species are allopolyploids. We collected ~400 samples from four allopolyploid species and their four diploid progenitor species. Based on chloroplast data and amplicon sequencing of 30 low-copy nuclear genes, we inferred a dated phylogeny that confirmed the homoploid hybrid origin of the Aegilops genus as well as the multiple maternal and paternal origins of the polyploid species. In addition, by jointly analysing our genomic data with geographical and climatic data, we found that allopolyploids combine both their diploid progenitors niches. This likely promoted faster recolonization of available suitable niches after the Last Glacial Maximum in allopolyploids as compared to their diploid progenitors. Moreover, this also confer higher adaptability potential to colonize new ecological niches.