PREFERENTIAL SENSITIVITY OF ACROCENTRIC CHROMOSOMES TO THE ANEUGENIC EFFECT OF COLCHICINE

In order to evaluate the predisposition to the aneuploidy-inducing age nt colchicine (Col) on lymphocytes from trisomic 21 patients compared with their parents and with a control group of subjects without trisom ic children, we performed the micronucleus (MN) assay associated with C-banding, CREST staining, and nucleolar organizing region (NOR)-bandi ng. According to our results Col behaves as an aneugenic agent indepen dently of the population studied for CREST and C-banding. The Col-indu ced MN exhibited a clear majority (>80%) of positive NOR-MN, meaning t hat they contain a NOR region transcriptionally active or inactive. Th e same data were observed in trisomic 21 individuals, their parents, a nd the control group, without significant differences between them. Th ese results seem to suggest a preferential effect of the aneugen Col o n acrocentric chromosomes in all of the three groups studied. (C) 1997 Wiley-Liss, Inc.