Nucleotide sequences of the 5.8S rRNA gene and internal transcribed spacer regions in carrot and broad bean ribosomal DNA.

Nucleotide sequences of the first and second internal transcribed spacers (ITS1 and ITS2, respectively) of ribosomal DNA (rDNA) from two dicot plants, carrot and broad bean, were determined. These sequences were compared with those of rice, a monocot plant, and other eukaryotic organisms. Both types of ITS region in some species of Angiospermae were the shortest among all eukaryotes so far examined and showed a wide range of variation in their G+C content, in contrast to a general trend toward very high G+C content in animals. Phylogenetic relationships of plants with animals and lower eukaryotes were considered using the nucleotide sequences of carrot and broad bean 5.8S rDNA that were determined in the present study, together with that of wheat 5.8S rRNA, which has been reported previously.