Structural Organization of 5S Ribosomal DNA in Rosa rugosa

摘要

For studying the molecular organization of the genomic region coding for 5S rRNA in the diploid species Rosa rugosa, several 5S rDNA repeat units were cloned and sequenced. An analysis of the obtained sequences revealed that in the genome only one length variant of the 5S rDNA repeated unit is present that contains intact promoter elements in the intergenic spacer (IGS) and appears to be transcriptionally active. In addition, a limited number of 5S rDNA pseudogenes were detected with a complete loss of the IGS and a portion of the coding region. The high level of sequence similarity (from 93.7 to 97.5%), revealed by comparing the IGS of the major 5S rDNA variants of East Asian R. rugosa and North American R. nitida, indicates a relatively recent divergence of these species.