What are germ cells?

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Germ cells are the precursors of gametes.

Gametes are sex cells that are produced via the process of meiosis. Gametes are haploid. This means that gametes contain half of the genetic material of a somatic (body) cell. Thus, we refer to somatic cells as being “diploid”.

Gametes are haploid because, during meiosis, the genetic material of an organism is replicated once but then undergoes two cellular divisions. Thus, during meiosis, one diploid parent cell produces four haploid gametes.

Two gametes, a sperm and an egg, combine during the process of fertilization to create a zygote. The fact that gametes are haploid ensures that the number of chromosomes that is unique to a species is maintained generation after generation. For example, a somatic cell of humans contains 46 chromosomes. Each gamete of a human contains 23 chromosomes. Thus, upon fertilization, the diploid number of 46 chromosomes is restored.

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