Quantitative studies on the arrangement of human metaphase chromosomes. IX. Arrangement of chromosomes with and without spindle apparatus.

The spatial relationships in human male metaphase cells treated with and without colcemide were compared with each other. The following results were obtained: (1) In normal male metaphases the overall distributions of chromosomal distances regardless of chromosome identification numbers did not show normal distribution, neither in the colcemid-free sample nor in the colcemide-treated sample. (2) In both samples larger chromosomes showed a more peripheral position, and smaller chromosomes showed a more central position. This finding was statistically significant. (3) No differences between the two samples could be observed concerning the following parameters: overall distributions of the centromere-centromere distances, distributions of the distances between the homologous chromosomes (except the small acrocentric chromosomes), rank positions of the mean distances between homologous chromosomes, and rank positions of the mean distances of the different chromosomes from the center of the mitosis (except few chromosomes). (4) Visible, but not statistically accessible, differences appeared between the two samples in respect to rank positions of the mean distances of all possible acrocentric pairing groups, rank positions of the mean distances of the homologous acrocentric chromosomes from the center of the mitosis, and distances of the X chromosome from the center of the mitosis. (5) Statistically significant differences appeared between the two samples with respect to distance distributions of the small acrocentric chromosomes and positions of the chromosomes 1, 16, 18, Y, and 21, 22 in relation to the center of the mitosis.