Does congression failure result in increased aneuploidy?
Our previous observations on human oocytes from unstimulated ovaries led us to speculate that failure of normal chromosome alignment might be associated with human age-related non-disjunction (Volarcik et al., 1998). If so, we would predict that: (i) cells exhibiting congression failure are capable of initiating anaphase; and (ii) failure to properly align chromosomes at the spindle equator predisposes to non-disjunction at anaphase I. As detailed above, the results of our analyses of oocytes from XYPOS females provided no evidence for a delay in anaphase onset in the presence of congression failure. Thus, our observations are consistent with the first of the two predictions. To test the second prediction, i.e. that congression failure predisposes to chromosome missegregation at anaphase, we analysed chromosome preparations of MII arrested oocytes from XYPOS females. Previous studies of MII arrested oocytes from XYPOS females suggested an increase in aneuploidy levels (Hunt and LeMaire
