title: Ribosomal RNA genes in the nucleus and chloroplast of Euglena.
abstract: Centrifugation of DNA from Euglena gracilis in Hg2+-CS2SO4 equilibrium gradients allows the chloroplast DNA to be separated clearly from the nuclear DNA. Cytoplasmic ribosomal RNA isolated from a heat-bleached strain hybridizes only to the nuclear DNA. The ribosomal RNA cistrons in the chloroplast DNA are not related to those in the nuclear DNA. A possible origin for the chloroplast genome is suggested by the observation that roughly one-fourth of the ribosomal RNA complementary sequences in chloroplast DNA anneal with RNA from the blue-green alga Anacystis nidulans.
mesh_terms: D001665:Binding Sites; D005075:Biological Evolution; D002467:Cell Nucleus / Q000032:analysis*; D002736:Chloroplasts / Q000032:analysis*; D000458:Cyanobacteria / Q000032:analysis; D004247:DNA / Q000032:analysis; D005056:Euglena gracilis / Q000032:analysis*; D005796:Genes; D008628:Mercury; D009693:Nucleic Acid Hybridization; D012313:RNA / Q000032:analysis*; D012270:Ribosomes / Q000032:analysis*; D013045:Species Specificity
chemical_list: D012313:RNA; D004247:DNA; D008628:Mercury