Polyploidy, the result of whole-genome duplication (WGD), is a major driver of eukaryote evolution. Yet WGDs are hugely disruptive mutations, and we still lack a clear understanding of their fitness consequences. Here, we study whether WGDs result in greater diversity of genomic structural variants (SVs) and how they influence evolutionary dynamics in a plant genus, Cochlearia (Brassicaceae). By using long-read sequencing and a graph-based pangenome, we find both negative and positive interactions between WGDs and SVs. Masking of recessive mutations due to WGDs leads to a progressive accumulation of deleterious SVs across four ploidal levels (from diploids to octoploids), likely reducing the adaptive potential of polyploid populations. However, we also discover putative benefits arising from SV accumulation, as more ploidy-specific SVs harbor signals of local adaptation in polyploids than in diploids. Together, our results suggest that SVs play diverse and contrasting roles in the evolutionary trajectories of young polyploids.

• MeSH
• duplikace genu * MeSH
• genom rostlinný * genetika   MeSH
• molekulární evoluce * MeSH
• mutace MeSH
• polyploidie * MeSH
• strukturální variace genomu genetika   MeSH
• Publikační typ
• časopisecké články MeSH

Relative contributions of pre-existing vs de novo genomic variation to adaptation are poorly understood, especially in polyploid organisms. We assess this in high resolution using autotetraploid Arabidopsis arenosa, which repeatedly adapted to toxic serpentine soils that exhibit skewed elemental profiles. Leveraging a fivefold replicated serpentine invasion, we assess selection on SNPs and structural variants (TEs) in 78 resequenced individuals and discover significant parallelism in candidate genes involved in ion homeostasis. We further model parallel selection and infer repeated sweeps on a shared pool of variants in nearly all these loci, supporting theoretical expectations. A single striking exception is represented by TWO PORE CHANNEL 1, which exhibits convergent evolution from independent de novo mutations at an identical, otherwise conserved site at the calcium channel selectivity gate. Taken together, this suggests that polyploid populations can rapidly adapt to environmental extremes, calling on both pre-existing variation and novel polymorphisms.

• MeSH
• alely * MeSH
• Arabidopsis účinky léků   genetika   MeSH
• fyziologická adaptace účinky léků   genetika   MeSH
• genom rostlinný * MeSH
• jednonukleotidový polymorfismus MeSH
• mutace MeSH
• polyploidie * MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• půda chemie   MeSH
• sekologanin-tryptaminové alkaloidy metabolismus   MeSH
• vápníkové kanály metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• proteiny huseníčku MeSH
• půda MeSH
• sekologanin-tryptaminové alkaloidy MeSH
• serpentine (alkaloid) MeSH Prohlížeč
• TPC1 protein, Arabidopsis MeSH Prohlížeč
• vápníkové kanály MeSH