Meiosis produces genetically distinct egg or sperm cells through specialized chromosome separation. It reduces the chromosome number by half and creates haploid reproductive cells.
Meiosis involves two successive divisions after one round of DNA replication. During meiosis I, homologous chromosome pairs separate. During meiosis II, sister chromatids separate. The result is usually four genetically different haploid cells from one starting cell.
Genetic diversity arises through crossing over between homologous chromosomes and through the independent assortment of chromosome pairs. Fertilization later combines genetic material from two haploid gametes and restores the diploid chromosome number.
Mitosis is different: it generally produces two genetically similar daughter cells for growth, maintenance, or asexual reproduction. Meiosis occurs in cells that give rise to gametes, although the exact stages and products differ between human sperm and egg formation.