Table 1.

Main types of non-surrounded “nucleolus” (NSN)-related and surrounded “nucleolus” (SN)-related configurations of chromatin in mammalian germinal vesicle (GV) oocytes, with reference to the original nomenclature including the karyosphere.

Animal	NSN Configurations (No Karyosphere)	SN-Like Configurations		References
		Intermediate Configurations without Prominent NLB-Associated Heterochromatin Rim (Karyosphere), Demonstrating Various Extent of Chromatin Condensation	Chromatin Configurations With Complete Karyosphere
Mouse	NSN Chromatin is not arranged around the NLB and occupies the whole nucleus	Partly NSN (pNSN) Some aggregates of chromatin are opposed to the NLB (no karyosphere) Partly SN (pSN) A discontinuous heterochromatin rim exists around the NLB (incomplete karyosphere)	SN A prominent NLB–heterochromatin complex (karyosphere) exists. Condensed chromatin entirely surrounds the NLB	[14,29,30]
Rat	Dictyate stage (stage 1) Chromatin threads are distributed through the nucleus	Late Dictyate Stage (stage 2) The “emptiness” of the nucleus is observed (which is apparently due to a karyosphere begins to form)	Chromatin Mass (stage 3) Similar to the SN stage (karyosphere) in the mouse	[31]
Rabbit	NSN Diffuse, filamentous chromatin is distributed through the nucleus	SC (singly condensed) Chromatin is condensed into a single large clump (karyosphere); nucleoli disappeared completely	Net-Like (NL) Chromatin is condensed into a net-like structure and surrounds small nucleoli/NLBs (incompact karyosphere) Loosely Condensed (LC) Chromatin forms irregularly-shaped clumps scattered throughout the nucleoplasm, or surrounds the nucleoli/NLBs (incompact karyosphere) Tightly Condensed (NC) Chromatin further condenses, forming larger clumps with regular edges that are distributed throughout the nucleoplasm or around the nucleoli/NLBs (incompact karyosphere)	[32]
Human	NSN Diffusely distributed chromatin	Class A The NLB is partially surrounded by chromatin that is also distributed throughout the nucleus (no karyosphere)	Class B All the chromatin surrounds the NLB (a fully formed compact karyosphere) Class C Chromatin surrounds the NLB; masses of condensed chromatin are also distributed throughout the nucleus (incompact karyosphere) Class D The NLB is surrounded by chromatin; threads of dispersed chromatin are distributed throughout the nucleoplasm (incompact karyosphere)	[21,22,33]
Monkey	GV1 Unrimmed oocytes	GV2 NLBs are partially rimmed by chromatin (incomplete karyosphere)	GV3 NLBs are completely rimmed by chromatin (a fully formed compact karyosphere)	[34]
Pig	NSN Diffuse and filamentous chromatin is distributed throughout the nuclear area Prematurely-condensed NSN (cNSN) Similar to NSN, but chromatin is condensed into solid masses distributed through the nucleoplasm	Partly NSN (pNSN) Chromatin begins to condense, particularly in the region around the NLB Prematurely-Condensed pNSN (cpNSN) Early NLB-associated heterochromatin rim (karyosphere) is already exists, but many chromatin blocks are also visible outside	Partly SN (pSN) Similar to SN, but condensed chromatin is distributed in a wider area of the nucleus (incompact karyosphere) Prematurely-Condensed pSN (cpSN) Similar to SN, but single heterochromatin blocks are present outside the karyosphere, resembling mouse SN SN All the chromatin surrounds the NLB (a fully formed compact karyosphere), as in human Class B oocytes	[20]
Dog	Diffuse Chromatin is homogeneously distributed throughout the nucleoplasm	Partly Grouped Chromatin is partly gathered around the nucleolus/NLB (incomplete karyosphere)	Grouped Chromatin is restricted to a specific area of the nucleus, surrounding the NLB (a fully formed compact karyosphere)	[27]
Cat 1	Chromatin occupies most of the oocyte nucleus, and a reticular chromatin configuration persists during follicular development	N/A		[24]
Cattle	NSN Diffuse, filamentous chromatin occupies the whole nuclear volume	Net-Like (N) Configuration Condensed chromatin forms a net-like structure in the nucleoplasm, but does not surround the NLBs Clumped (C) Configuration Chromatin condensed into large clumps is usually located in the vicinity of the nuclear envelope but does not surround the NLBs Floccular (F) Configuration Floccular chromatin is located near the NLBs and nuclear envelope	SN NLBs are surrounded by condensed chromatin (karyosphere)	[35]
Sheep	NSN Diffuse chromatin occupies the whole nuclear volume	N/A	SN Condensed chromatin surrounds the nucleolus SNE (specific for sheep) Condensed chromatin is observed near the nucleolus and the nuclear envelope	[25]
Horse	Fibrillar Strands of chromatin are located through the nucleoplasm Intermediate Strands or irregular chromatin masses occupy over half of nucleus	Fluorescing Nucleus (FN) The nucleus displays diffuse or spotty chromatin	Loosely Condensed Chromatin (LCC) Looks as an incompact karyosphere Tightly Condensed Chromatin (TCC) Chromatin is organized in a single irregular or circular mass, usually surrounding a nucleolar derivative/NLB (compact karyosphere)	[36,37]
Goat 1	GV1 Chromatin is distributed throughout the nucleoplasm, exhibiting a diffuse, filamentous pattern; one or two large nucleoli exist	GV2 (GV2n/GV2c) One or two medium sized nucleoli exist; chromatin forms a net-like structure throughout the nucleoplasm (GV2n) or condenses into several large clumps (GV2c) GV3c The nucleus contains small nucleoli similar to those of GV3n, but the chromatin is condensed further into several large clumps GV3n One or two small nucleoli exist; chromatin condenses into a net-like structure over the nucleoplasm GV4 (orphan) chromatin is clumped, but no nucleoli are observed	N/A	[23]
Ferret	FC (fibrillar chromatin) Chromatin strands occupy most of the nuclear volume	Intermediate Condensed Chromatin (ICC) Dense, irregular chromatin masses are distributed throughout the nucleus	Condensed Chromatin (CC) Chromatin is highly compact and centered around the nucleolus, forming a compact karyosphere	[28]

¹ No typical karyosphere found in any stage. N/A, no similar stage determined; NLB, nucleolus-like body; original terms are italicized.