Mitosis and Somatic Mutations
Normal human cells with a nucleus having 23 pairs of chromosomes are called diploid or 2N to indicate these homolog pairs. During the cell growth cycle for body (somatic) cells, the DNA of all 23 pairs--46 chromosomes--copies itself (4N). When the cell next divides by a process called mitosis, each daughter cell ends up with 23 pairs or 2N, a complete set of chromosomes. If a mutation occurs during the process of mitosis, only the offspring of the mutated somatic cell will have the alteration present.