It is found in the cells of animal and plant and yeast and there is more than one nucleolus in one nucleus.

• 核仁主要由FC (fibrillar center) 和DFC (dense fibrillar component) 以及GC (granular component) 等超微结构组成，普遍存在于动物细胞，植物细胞和酵母细胞核中。