Chromosome malsegregation induced by methanol in Drosophila melanogaster females.

Methanol (MeOH) is a colorless, flammable, poisonous, alcohol that causes intoxication by ingesting, inhaling or by contact with formulations that include it. It is produced in large volumes and there is high level of human exposure, especially by the inhalation route. It has been reported as innocuous in various test systems; thus, the aim of this work was to search for in vivo genotoxic effects of MeOH in Drosophila melanogaster, studying its ability to induce nondisjunction (ND) in females. Treatments were acute (60 min) and via inhalation. It was toxic in 1-day old flies (MI = 63 % for 75 % MeOH) and in 5-days old flies (MI = 8.4 %, 40 % MeOH). Female fertility was severely affected during the first 24 h after treatment, later control values were recovered. MeOH induced a 16-fold increase of ND (%) in 1-day old females, and a 9-fold rise in 5-days old female's offspring, but control values were recovered in the offspring of subsequent broods. These findings suggest that the main effect of MeOH is to induce chromosomal malsegregation when present at the resumption of M-phase I after fertilization, probably due to perturbations in the nuclear membrane. Therefore, negative results with assays that evaluate DNA damage do not imply that the compound tested is not a potential hazard because other cellular components could be modified.