Biopolymers and cell. 2000; 16 (3): 205 - 211

Organization and evolution of the Nicotiana 5S rRNA genes

S. I. Komarnytsky, I. K. Komarnytsky

Structure organization and evolution of SS ribosomal RNA genes in the genus Nicotiana have been studied. These genes have been shown to be clustered, tandem repeated, and extensively methylated. Two classes of SS rDNA are mainly characteristic for the species of n - 24 ploidy level while the species of n- 12 ploidy level possess a single class, with the minor exceptions. The tendency of 5S rRNA repeats to evolve by concerted decrease of their length has been clearly shown in Australian tobaccos.