A diploid cell in a human testis undergoes meiosis. Explain why the four daughter cells produced at the end of meiosis are genetically different from each other.

Meiosis consists of two successive divisions, not one, so each cell goes through two rounds of chromosome separation.

During the first division the homologous chromosomes are separated, and during the second division the sister chromatids are separated. In both divisions the chromosomes are randomly assorted, so the alleles that end up in each daughter cell are mixed.

Each daughter cell receives only one set of chromosomes – a haploid number – which is half the chromosome number of the original diploid cell.

Because the chromosomes and alleles are shuffled and each cell gets a different combination, the four gametes are genetically distinct; no two cells have the same set of alleles, and new allele combinations can arise if mutations occur.