减数分裂Ⅱ

Cells formed during meiosis one divide during meiosis two, creating new ones that will develop into mature gametes, like sperm.

In humans, prophase two initiates meiosis two, where dense, X-shaped chromosomes begin to appear in a haploid cell's nucleus. Every X consists of a centromere and joined sister chromatids, each containing a unique combination of maternal and paternal material caused by crossing over during meiosis one.

Meanwhile, in the cell's cytoplasm, the centrosomes travel to opposite poles, and the microtubule-based meiotic spindle apparatus again develops between them.

Prometaphase two is characterized by nuclear envelope disintegration and free-floating chromosomes. Kinetochores also materialize on the centromeres and serve as anchors for extending microtubules. This results in the meiotic spindles securing sister chromatids in a pair to opposing centrosomes.

Continuing to metaphase two, the microtubules orient the chromosomes along the equator and during anaphase two, these structures truncate, tugging sister chromatids apart while the cell also stretches.

With telophase two, the chromatids are delivered to opposite edges and each such aggregation constitutes one h