Germ-line cells (2n = diploid) are produced in organs called gonads (ovaries and testes).

These cells undergo meiosis to form haploid gametes (eggs and sperm, n = haploid).

The rest of the diploid body cells are called somatic cells and reproduce by mitosis.

Fertilization from the fusion of gametes creates the diploid zygote, which undergoes many rounds of mitosis to produce the organism.