Mitosis

Definition

The nuclear division phase of the eukaryotic cell cycle in which replicated chromosomes are segregated into two identical sets, producing two daughter nuclei with the same chromosome number and genetic content as the parent cell. Mitosis consists of prophase, metaphase, anaphase, and telophase, typically followed by cytokinesis. In arthropods, mitosis drives post-embryonic growth through cell proliferation in regenerating limbs, developing wing discs in holometabolous insects, and the massive expansion of ovarian tissue during vitellogenesis.

Etymology

Greek mitos, thread, referring to the thread-like appearance of chromosomes during division

Example

In the developing leg of a cricket nymph, repeated rounds of mitosis in the regenerating blastema restore the exact segmental pattern and proportions of the missing tibial and tarsal segments.

Synonyms

• karyokinesis
• equational division

Related Terms

• Meiosis
• cytokinesis
• cell cycle
• Chromosome
• spindle apparatus
• blastema
• apoptosis

Usage Notes

Distinguished from meiosis, which is a reductional division producing haploid cells with recombined genetic material. Mitosis maintains diploidy and genetic identity; meiosis generates diversity and halves chromosome number. In arthropodology, 'mitosis' is used absolutely (not relative to another structure), though the rate of mitosis varies dramatically between tissues—high in imaginal discs and regenerating epidermis, absent or rare in most adult neurons.