During anaphase II of meiosis, which event occurs?

• A. The spindle fibers disappear and a nuclear membrane forms around each set of chromosomes.
• B. Centromeres divide and chromatids move to opposite poles of the cell.
• C. Crossing over occurs between homologous chromosomes.
• D. Cytokinesis occurs after telophase II.

Answer: (B)

During meiosis II, the main event of this stage is the separation of sister chromatids. The centromeres split as cohesin proteins are cleaved, and the chromatids—now individual chromosomes—are pulled to opposite poles by shortening kinetochore microtubules. This ensures that each daughter cell ends up with a haploid set of chromosomes.

This differs from what happens in other stages: the formation of a new nuclear membrane and the dissolution of spindle fibers occur during telophase, not anaphase. Crossing over takes place in prophase I, between homologous chromosomes. Cytokinesis occurs after telophase II, when the cytoplasm divides.