Polyploidisation or whole genome duplication (WGD), is a widespread phenomena amongst

Eukaryotes but is especially abundant in the plant lineage. The extra genome copy can open a road

to evolutionary success by providing genetic material that is free to evolve new functionalities.

Nevertheless, WGD is generally not well tolerated due to subsequent changes in cell geometry and

genomic shock. Consequently the successful establishment of polyploids is somewhat shrouded in

mystery. Previous work in our lab revealed that many plant polyploids became established during

the Cretaceaus-Paleogene mass extinction. Because present-day polyploids are especially

abundant in stressful environments as the arctic and polyploids might have a higher adaptive

potential due to their increased genetic variation and changes in gene expression, stressful

conditions could be a catalyst for the polyploid establishment. Here we propose the use of a long

term evolutionary experiment to test this hypothesis, to assess the effect of the evolutionary

distance between the two genomes brought together and to study the stabilisation of the

polyploid genome. First, we will construct polyploid strains. Second, we will subject them to a wide

variety of stressors and monitor their ploidy level and fitness. Finally a few successful lineages will

be selected and the genomic features that allow their success will be identified by sequencing

their complete genomes every few generations.