IMPORTANT BIOLOGICAL VARIABLES THAT CAN INFLUENCE THE DEGREE OF CHEMICAL-INDUCED ANEUPLOIDY IN MAMMALIAN OOCYTE AND ZYGOTES

The ability of certain chemicals to increase the frequency of aneuploi dy in mammalian oocytes elicits concern about human health and well-be ing. This concernment exists because aneuploidy is the most prevalent class of human genetic disorders, and very little information exists a bout the etiology of aneuploidy. Although there are experimental model s for studying aneuploidy in female germ cells and zygotes, these mode ls are still being validated because insufficient information exists a bout the biological variables that can influence the degree of chemica l-induced aneuploidy. In this regard, variables such as dose, solvent, use of gonadotrophins, mode and preovulatory time of chemical adminis tration, time of cell harvest relative to the possibility of chemical- induced meiotic delay, criteria for cytogenetic analysis and data repo rting, and an introduction to differences between cell types and sexes are presented. Besides these variables, additional information is nee ded about the various molecular mechanisms associated with oocyte meio tic maturation and the genesis of aneuploidy. Also, differences betwee n the results from selected chromosome analysis and DNA-hybridization studies are presented. Based upon the various biologic endpoints measu red and the differences in cellular physiology and biochemical pathway s, agreement among the results from different aneuploidy assays cannot necessarily be expected. To gain further insight into the etiology of aneuploidy in female germ cells, information is needed about the chem ical interactions between endogenous and exogenous compounds and those involved with oocyte meiotic maturation.