Chromosome-level assemblies of multiple Arabidopsis genomes reveal hotspots of rearrangements with altered evolutionary dynamics

摘要

Despite hundreds of sequenced Arabidopsis genomes, very little is known about the degree ofgenomic collinearity within single species, due to the low number of chromosome-levelassemblies. Here, we report chromosome-level reference-quality assemblies of seven Arabidopsisthaliana accessions selected across its global range. Each genome reveals between13–17 Mb rearranged, and 5–6 Mb non-reference sequences introducing copy-numberchanges in ~5000 genes, including ~1900 non-reference genes. Quantifying the collinearitybetween the genomes reveals ~350 euchromatic regions, where accession-specific tandemduplications destroy the collinearity between the genomes. These hotspots of rearrangementsare characterized by reduced meiotic recombination in hybrids and genes implicated inbiotic stress response. This suggests that hotspots of rearrangements undergo alteredevolutionary dynamics, as compared to the rest of the genome, which are mostly based onthe accumulation of new mutations and not on the recombination of existing variation, andthereby enable a quick response to the biotic stress.