No, sperm and eggs are not formed by mitosis. They are formed by a specialized type of cell division called meiosis.
Understanding Mitosis and Meiosis
- Mitosis is a type of cell division that creates two identical daughter cells from a single parent cell. This process is crucial for growth and repair in somatic cells (all cells in the body except reproductive cells).
- Meiosis, on the other hand, is a reductional cell division that produces four genetically unique haploid daughter cells (gametes) from a single diploid parent cell. This process is essential for sexual reproduction, creating sperm and egg cells with half the number of chromosomes as the parent cell. When a sperm and egg unite during fertilization, the resulting zygote has the full complement of chromosomes.
The provided references explicitly state that germ cells (which produce sperm and eggs) undergo meiosis, not mitosis: "Whereas somatic cells undergo mitosis to proliferate, the germ cells undergo meiosis to produce haploid gametes (the sperm and the egg)." Furthermore, multiple sources confirm that meiosis is the specific process responsible for creating sperm and egg cells.
One reference mentions that after fertilization, the resulting embryo undergoes mitotic divisions: "With Meikin gone and the rewiring of cell division reversed, eggs and sperm are ready for mitosis; should they fuse and form an embryo, that is the next cell…" This highlights that while meiosis creates the gametes, mitosis is vital for the subsequent development of the embryo.
In summary, while mitosis plays a crucial role in embryonic development after fertilization, the formation of sperm and egg cells themselves is exclusively the result of meiosis.
