Nucleolus organizer region

[1] The exact sequence of these regions is not included in the human reference genome as of 2016[1] or the GRCh38.p10 released January 6, 2017.

[5] There are also DNA sequences related to rDNA that are on other chromosomes and may be involved in nucleoli formation.

[1] UBF has been identified as a mitotic "bookmark" of expressed rDNA, which allows it to resume transcription quickly after mitosis.

[1] The distal flanking junction (DJ) of the NORs has been shown to associate with the periphery of nucleoli.

[4] rDNA operons in Escherichia coli have been found to cluster near each other, similar to a eukaryotic nucleolus.