Ribosomal 45S rRNA genes outside of clusters
ribosomal 45s rrna genes outside of clusters
These 45S pre-ribosomal RNA genes, and the 18S, 28S and 5.8S rRNA which may be processed from each 45S rRNA shown below, are found outside of the 13p12, 14p12, 15p12, 21p12 and 22p12 rRNA clusters that are the sites of rRNA transcription in the nucleolus. Therefore it is not certain whether these genes would be transcribed into functional rRNA molecules. To denote this, each gene symbol has the letter 'N' before its numerical identifier.