The large genome size variation in the Hesperis clade was shaped by the prevalent proliferation of DNA repeats and rarer genome downsizing

摘要

Most crucifer species (Brassicaceae) have small nuclear genomes (mean 1C-value 617 Mb). The species with the largest genomes occur within the monophyletic Hesperis clade (Mandáková et al., Plant Physiology174: 2062–2071; also known as Clade E or Lineage III). Whereas most chromosome numbers in the clade are 6 or 7, monoploid genome sizes vary 16-fold (256–4264 Mb). To get an insight into genome size evolution in the Hesperis clade (~350 species in ~48 genera), we aimed to identify, quantify and localize in situ the repeats from which these genomes are built. We analysed nuclear repeatomes in seven species, covering the phylogenetic and genome size breadth of the clade, by low-pass whole-genome sequencing.