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How does meiosis produce reproductive cells with half the usual chromosome number?

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Meiosis is a specialized form of cell division that reduces the chromosome number by half to produce gametes. This process involves two successive nuclear divisions starting from a diploid germ cell.1

Prior to division, each chromosome replicates into two joined chromatids. During the first division (meiosis I), homologous chromosomes pair up and then separate, moving to opposite poles of the cell. Because the sister chromatids remain attached during this stage, each resulting daughter cell receives only one chromosome from each homologous pair, effectively halving the chromosome count.12

In the second division (meiosis II), the sister chromatids of each chromosome are pulled apart, similar to mitosis. This division does not further reduce the chromosome number but ensures each of the four final haploid cells contains a single copy of each gene. When fertilization occurs, the fusion of two such gametes restores the original diploid number in the zygote.12