Telomere and centromere association tendencies in the human male metaphase complement

"Generalized distances" between centromeres and between telomeres were statistically analyzed (chi 2 tests) in 100 trypsin-banded metaphase figures derived from normal males. Analysis of association tendencies on the first column of obtained c-c, p-p, q-p, and p-q histograms showed significant heterochromatin attraction not only between nonacrocentrics and acrocentrics but also between two nonacrocentric chromosome pairs (1 and 16). However since not all c-heterochromatin-rich chromosomes were involved in associations (pair 5), and conversely, since chromosomes without an important centromeric heterochromatin block were involved in associations (pairs 8 and 11), it is probable that centromeric heterochromatin is not the only factor responsible for chromosome association. Moreover associations occur not only at the centromeres; in our circle analysis of the binding capacity of the telomeres or centromere of one chromosome pair with the telomeres or the centromeres of all other chromosome pairs, we also found preferential associations for T(4,13), T(9,15), T(11,15), T(13,19), T(15,19), T(17,18), T(17,22), and T(19,20). We therefore suggest that heterochromatin is not the only reason for chromosome association and that telomeres may also play an important part in this process.