The "loss" of centromeres from chromosomes of aged women.

Both aneuploid cells in mitosis and nondisjunction in meiosis increase with advancing age. The cause(s) of these phenomena remains unknown. Here, it was confirmed that a positive Cd-band reflects the presence of a functioning centromere while a negative reaction is indicative of its inactivation or loss. We applied the Cd-banding technique to mitotic spreads obtained from 14 aged and 13 control females (peripheral blood culture). Of 6,474 scored chromosomes from the aged women, 62(0.96%) were Cd-negative; this was the case in 12 of 3,861 (0.31%) chromosomes from the younger controls. The difference was highly significant (P less than .001). About 60% of the 62 Cd-negative chromosomes from aged women belong to the C group. Chromosomes from six of the 14 aged females were additionally examined by either the C-band or the distamycin-DAPI technique; of 2,080 chromosomes, 13 (0.63%) showed premature separation of their centromeres (control: 7/5, 080, 0.14%). Our findings suggest that in aged women, the chromosomes tend to lose their Cd-positive material and the function of the centromere.