Plant genome evolution: lessons from comparative genomics at the DNA level.

Angiosperm genomes show tremendous variability in genome size and chromosome number. Nevertheless, comparative genetic mapping has revealed genome collinearity of closely related species. Sequence-based comparisons were used to assess the conservation of gene arrangements. Numerous small rearrangements, insertions/deletions, duplications, inversions and translocations have been detected. Importantly, comparative sequence analyses have unambiguously shown micro-collinearity of distantly related plant species. Duplications and subsequent gene loss have been identified as a particular important factor in the evolution of plant genomes.