A structure found most metazoan nucleoli, but not usually found in lower eukaryotes; surrounded by the dense fibrillar component; the zone of transcription from multiple copies of the pre-rRNA genes is in the border region between these two structures. [ http://www.ncbi.nlm.nih.gov/pubmed/10754561 ]
Synonyms: fibrillar centre
This is just here as a test because I lose it