CHARACTERIZATION AND PHYLOGENETIC DISTRIBUTION OF A CHLOROPLAST DNA REARRANGEMENT IN THE BERBERIDACEAE

Restriction site maps and a clone bank of chloroplast DNA (cpDNA) of M ahonia higginsae (MUNZ) AHRENDT (Berbericiaceae) were constructed. The size of Mahonia cpDNA was about 167 kb. Precise mapping using gene pr obes revealed that cpDNA of M. higginsae has an inverted repeat (IR) 1 1.5 kb larger than the tobacco IR. The expansion of the IR into the la rge single copy region has resulted in the duplication of at least ten genes including psbB. The phylogenetic distribution of the expanded I R was examined in twenty-five species of Berberis and Mahonia, twenty species representing the fifteen remaining genera of the Berberidaceae , and four species from four allied families. Our survey indicates tha t only the species of the closely related genera Berberis and Mahonia share the 11.5 kb expansion of IR. This result supports their close ph ylogenetic relationship, which has been suggested previously by chromo somal, morphological, and serological data.