What can result from a failure of the spindle checkpoint?

Aneuploidy, the presence of an abnormal number of chromosomes in a cell, can occur as a direct consequence of a failure in the spindle checkpoint. This checkpoint, which takes place during the metaphase of mitosis, ensures that all chromosomes are properly attached to the spindle apparatus before proceeding with cell division. If this checkpoint fails, chromosomes may not align or separate correctly during anaphase. This can lead to one daughter cell receiving an extra chromosome (trisomy) while the other may be missing one (monosomy), resulting in aneuploidy.

The spindle checkpoint is a critical regulatory mechanism that maintains genetic stability, and its failure can lead to various consequences, including an increased risk of cancer, as cells with the incorrect chromosome number can proliferate uncontrollably. Thus, recognizing the role of the spindle checkpoint in preventing aneuploidy underscores its importance in the fidelity of cell division.