Where Nucleolar Organizer Region?

Nucleolus organizer regions (NORs) are chromosomal regions crucial for the formation of the nucleolus. In humans, the NORs are located on the short arms of the acrocentric chromosomes 13, 14, 15, 21 and 22, the genes RNR1, RNR2, RNR3, RNR4, and RNR5 respectively. These regions code for 5.8S, 18S, and 28S ribosomal RNA.

What is known as nucleolar organizer?

: the specific part of a chromosome with which a nucleolus is associated especially during its reorganization after nuclear division. — called also nucleolar organizer.

What is NOR and its function?

Nucleolus organizer regions or NORs are the certain regions found on the chromosomes which contains the genes for ribosomal RNA and helps in the formation nucleoli.