Table 1. Different patterns of rDNA chromatin organization at NOR-1 sites.

Individual	A	B	F	T
1	75	3	0	78
2	80	0	24	104
3	101	2	5	108
4	109	1	3	113
5	83	1	2	86
6	136	0	3	139
7	102	0	3	105
8	106	0	7	113
9	78	0	2	80
10	50	2	11	63
11	66	4	11	81
12	54	0	6	60

A number of cells with a particular rDNA chromatin topology at the NOR-1 sites was observed. A - one NOR-1 site shows a terminal rDNA knob and a proximal dispersed rDNA fraction, corresponding to decondensed rDNA chromatin, while another NOR-1 site contains a rDNA knob at the proximal and the distal (satellite) end with dispersed rDNA chromatin spreading between the two; B - one NOR-1 site shows proximal rDNA knob and a terminal dispersed rDNA fraction, the other site shows only condensed rDNA chromatin at the satellite, while rDNA chromatin from the proximal part of the site is dispersed; F - fusion of the sites, i.e. very close positioning of proximal rDNA knobs in relation of each other, T - total number of analyzed cells.