Fig. 3. Unfolding of the q-arm of chromosome 1. (A) Representative images of the CHR1 q-arm in sperm cells taken with triple-band-pass filter (DNA counterstained with DAPI, blue) or selective FITC-filter (green). (B) Selection of typical images of the CHR1 q-arm domain arranged in the order of nuclei size. L-length of the long nuclear axis. Position of the tail attachment (basal part of nuclei) is indicated by a star. Arrowheads in A and B show condensed heterochromatic regions and white lines the CEN domain. (C) Correlation between the lengths of CHR1 q-arm and the long nuclear axis in sperm cells. (D) The width of the CHR1 q-arm chromatin fibril does not depend on length of the long nuclear axis. D and C, solid bold lines show best-fit regression, dotted lines-confidence intervals. (E) Frequency distribution of the CHR1 q-arm widths registered over the wide interval of sperm nuclear sizes (0.4 µm>L<2.6 µm).