[Aneuploidy in man (facts and hypotheses)].

Mechanisms of the human aneuploidy formation are discussed proceeding from the review of the published data obtained by Soviet and foreign authors. It is supposed that hereditary determination of this process plays a main role as compared with new genomic mutations resulting from the induction by ecological factors. Microstructural rearrangements and nonhomologous recombination in nondisjunction of chromosomes during cell division are considered parallel with mosaicism as one of possible reasons of genetic predisposition.