RNR4 (RNA, ribosomal 45S cluster 4) is a human ribosomal DNA gene located on Chromosome 21. Tandem copies of this gene form one of five nucleolus organizer regions in the human genome, they are located on the chromosomes 13 (RNR1), 14 (RNR2), 15 (RNR3), 21 (RNR4), 22 (RNR5). == See also == Ribosomal RNA (rRNA) == References == == Further reading ==
