<i>Arabidopsis</i> family ties: molecular phylogeny and age estimates in Brassicaceae

ABSTRACT The Brassicaceae family is of great scientific interest because it contains the plant model organism Arabidopsis thaliana. Currently, contemporary plant research activities expand to other Brassicaceae taxa. Despite that, the phylogeny of this family is only partly understood. The present study deepens our understanding of a family‐wide phylogeny by using two new approaches in phylogenetic family‐wide research. We used a molecular marker from the mitochondrial genome and utilised a relaxed molecular dating method. Our data generally confirms a recent tribal alignment of Brassicaceae. We present for the first time a biogeographical scenario for the broad‐scale Brassicaceae evolution. We suggest that Brassicaceae most likely evolved some 19 mya in or near the eastern Mediterranean region from a common ancestor of its sister family Cleomaceae. The early Brassicaceae formed a lineage adapted to more open/drier habitats than its capparoid progenitors. The early Brassicaceae evolution was very rapid and the radiation was most likely driven by climatic changes that created open habitats and the well‐documented expansion of open grass‐dominated ecosystems. Moreover, our dating suggests that the radiation events correlate with an ancient genome duplication in the early history of the family, which is evidenced by recent genomic studies.