Chloroplast DNA variation among five species ofRanunculaceae: Structure, sequence divergence, and phylogenetic relationships

Abstract

A restriction site map of the chloroplast genome ofCaltha palustris L. (Ranunculaceae) has been constructed for 13 restriction endonucleases using filter hybridization with cloned tobacco chloroplast DNA fragments. A size of 153.8 kb has been estimated for theCaltha chloroplast genome. Forty-six chloroplast genes and four open reading frames have been mapped using small tobacco chloroplast gene probes. Chloroplast DNA sequence divergence has been estimated for all pairs of five species ofRanunculaceae, Caltha palustris, Ranunculus bulbosus, R. fascicularis, R. recurvatus, andTrollius ledebourii, and ranges between 0.2% and 9.6% for the total genome. Divergence values are much higher in the small and large single copy regions than in the inverted repeat. Phylogenetic relationships between the five species have been hypothesized using chloroplast DNA restriction site mapping. One hundred and six informative restriction site mutations have been detected using eleven restriction endonucleases. Cladistic analyses of the restriction site mutations have been performed using Wagner and Dollo parsimony algorithms, and confidence intervals have been calculated for the resulting monophyletic groups using bootstrapping. It is demonstrated that restriction site comparisons are applicable to theRanunculaceae on intergeneric level, with the exception of groups having extensive genomic rearrangements. Moreover, sequence divergence is low enough at the interspecific level to allow phylogenetic analyses within genera such asRanunculus.