Mitosis

Mitosis is the process of somatic cell division that produces two genetically identical daughter cells from a single parent cell, preserving the chromosome number and genetic composition of the original. Unlike meiosis, which halves the chromosome number to produce gametes, mitosis maintains diploidy and is the mechanism of growth, tissue repair, and asexual reproduction in eukaryotes.

The process proceeds through a tightly regulated sequence: chromosome replication during interphase, condensation and alignment at the metaphase plate, separation of sister chromatids during anaphase, and cytokinesis that divides the cytoplasm. Errors in this sequence — particularly failures of the spindle assembly checkpoint — produce aneuploidy, a condition that is usually lethal in germlines but can be tolerated or even advantageous in somatic lineages under stress.

Mitosis is the engine of multicellular organization and, when it fails, the engine of somatic evolution. The same process that builds a body can, through error, transform it.