There large inversions in the chloroplast genomes and one loss of the chloroplast gene rps16 suggest an early evolutionary split in the genus Adonis (Ranunculaceae)

Detailed chloroplast DNA restriction site maps for two species in the genus Adonis (Ranunculaceae), A. annua and A. vernalis, were constructed using single and double digests and the sizes of these genomes are 151.3 and 156.5 kilobases, respectively. Three inversions were found in Adonis, relative to the gene order in the majority of land plants. These rearrangements represent two different gene orders and mark an ancient split in the evolutionary history of this genus. Gene probes were used in order to map the endpoints of the inversions and the inverted repeat regions. The inverted repeat is approximately 400 base pairs shorter in A. annua than in A. vernalis. Two inversions, 39 kilobases and 24 kilobases in size, occur in A. annua surd one inversion, 42 kilobases in size, is present in the remaining investigated species of Adonis. The gene rps16 is absent from the chloroplast genome in Adonis annua. Restriction sites for eleven restriction endonucleases were mapped for A. annua, A. vernalis and four additional species of Adonis and two species of Trollius. Eighty-six phylogenetically informative sites were analysed cladistically in order to evaluate the main clades within Adonis.