Comparison of acrocentric associations in male and female cells. Relationship to the active nucleolar organizers.

This work deals with a computer-aided study of associations between trypsin-banded acrocentrics in different male and female samples in a total of 900 cells. In female samples, acrocentrics 21 appeared as the most frequently involved in associations, followed by chromosome 13, whereas in male samples cell associations seemed more randomly distributed in the different samples. In addition, investigations in one female subject showed a very high correlation between the frequency with which an acrocentric was found in association and the presence and size of its active rDNA genes as shown by silver staining followed by staining with acridine orange.

Non-random association of trypsin-banded human acrocentric chromosomes.

This paper deals with a computer-aided study of the associations between acrocentric chromosomes as well as between those other chromosomes which in our investigations were revealed to be significantly closer to each other than random. The chromosome pairs were identified by a trypsin-banding technique. The method used has been elaborated previously with the specific aim of determining associations in a manner that avoids all subjective criteria.

Stability of centromere-center distances in normal human metaphases.

Centromere-center distances were analyzed in 50 normal female and 100 normal male metaphases. Compared with the random distribution of all chromosomes, chromosome pair 6 had a significantly different distribution in both female and male metaphases. Moreover, a significant peripheral location of chromosome pairs 4 and 5 and a significant central location of chromosome pairs 13, 15, 21, and 22 were found in male metaphases.