THE GENETICS OF 5S RIBOSOMAL-RNA-ENCODING MULTIGENE FAMILIES IN BARLEY

Two loci containing genes encoding 5S rRNA were mapped on the second a nd third chromosomes of barley. The two gene clusters located on diffe rent chromosomes differed in the length of the nontranscribed spacer s eparating the 5S rRNA genes. All nontranscribed spacers contained a va riable number of trinucleotide tandem repeats. The distribution of 5S genes between these two clusters and their copy number varied widely b etween cultivars and doubled haploids derived from cross between two b arley cultivars. However, this variation had no obvious effect on plan t phenotype.