title: Structural features of the plastid ribosomal RNA operons of two red algae: Antithamnion sp. and Cyanidium caldarium.
abstract: The nucleotide sequences of the plastid 16S rDNA of the multicellular red alga Antithamnion sp. and the 16S rDNA/23S rDNA intergenic spacers of the plastid DNAs of the unicellular red alga Cyanidium caldarium and of Antithamnion sp. were determined. Sequence comparisons support the idea of a polyphyletic origin of the red algal and the higher-plant chloroplasts. Both spacer regions include the unsplit tRNA(Ile)(GAU) and tRNA(Ala)(UGC) genes and so the plastids of both algae form a homogeneous group with those of chromophytic algae and Cyanophora paradoxa characterized by 'small-sized' rDNA spacers in contrast to green algae and higher plants. Nevertheless, remarkable sequence differences within the rRNA and the tRNA genes give the plastids of Cyanidium caldarium a rather isolated position.
authors.affiliation: Institut für Pflanzenphysiologie, Justus-Liebig-Universität Giessen, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Maid
authors.forename: K
authors.initials: K
authors.lastname: Zetsche
mesh_terms: D001483:Base Sequence; D004275:DNA, Ribosomal / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012338:RNA, Ribosomal, 23S / Q000235:genetics*; D012344:RNA, Transfer, Ala / Q000235:genetics; D012355:RNA, Transfer, Ile / Q000235:genetics; D015183:Restriction Mapping; D000461:Rhodophyta / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D012344:RNA, Transfer, Ala; D012355:RNA, Transfer, Ile