(1) Benzer called this unit the ‘cistron’; molecular biologists came to view the cistron as the nucleotide sequence encoding a single polypeptide.(2) Molecular evolution of the rDNA cistron in these plants typically follows the same trajectory.(3) The estimate was defined at the scale of cistrons so as to exclude the possibility of recombination.(4) Almost all eukaryotes have multiple copies of their nuclear ribosomal RNA cistrons , arranged in a long tandem array.(5) We find that full function of the endogenous rDNA locus depends not merely on the presence of the rDNA cistrons but also on chromosomal context.
