What does endomitosis mean?
Endomitosis is a biological phenomenon in which the chromosomes inside a cell replicate, but the process stops short of actual division: the nuclear envelope never breaks down, no spindle separates the copies, and the cell itself never splits. The result is a single nucleus containing multiple sets of chromosomes, a state known as polyploidy. This contrasts with ordinary mitosis, which produces two daughter cells each carrying one complete genome. Endomitosis is best known from two settings: certain plant tissues, where it supports growth and specialization of cells that will no longer divide, and mammalian megakaryocytes, the bone-marrow cells that produce blood platelets, which use repeated rounds of endomitosis to build the large cytoplasmic volume needed for their job. The term appears almost exclusively in scientific writing on cytology and developmental biology, and it is closely related to, and sometimes used interchangeably with, endoreduplication.
nounA form of chromosome replication within a single nucleus in which the chromosomes duplicate but the nuclear envelope does not break down and the cell does not divide, producing a polyploid nucleus. It occurs notably in certain plant tissues and in mammalian megakaryocytes.
- Chromosome replication within an intact nucleus without nuclear or cellular division, producing polyploid cells.
"Megakaryocytes undergo repeated rounds of endomitosis to become polyploid."
"In plants, endomitosis is common in cells that will eventually differentiate without further division."
"Repeated cycles of endomitosis allow megakaryocytes to increase their cytoplasmic volume for platelet production."
Rarely used; the word normally functions as an uncountable mass noun referring to the process generally.
"Multiple endomitoses were observed in the developing tissue."
Some cells copy their DNA over and over without ever dividing — a megakaryocyte can end up with up to 128 times the normal amount of DNA packed inside one nucleus.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of endomitosis
The word combines three elements of Greek origin: the prefix "endo-" meaning "within" (from Greek éndon), "mito-" from Greek mîtos meaning "thread" (a reference to the thread-like appearance of chromosomes), and "-osis," a Greek-derived suffix denoting a process or condition. It was coined in the twentieth century by biologists as a variant of "mitosis" to describe chromosome duplication occurring entirely inside the intact nucleus. It shares its roots with related cytological terms such as mitosis, amitosis, and karyokinesis.
Related word forms
How endomitosis is actually used
Strictly technical vocabulary used almost exclusively in cell biology and cytology literature; not encountered in general conversation. Some researchers use it interchangeably with "endoreduplication," though careful writers distinguish them by whether an aborted mitotic event occurs.
Easily confused with endomitosis
Mitosis is the normal process of nuclear division into two daughter nuclei, whereas endomitosis is chromosome replication without any division of the nucleus or cell.
Endoreduplication refers specifically to repeated genome replication within one cell cycle without mitosis; the terms overlap heavily and are often used interchangeably, though some authors reserve endomitosis for cases where an abortive mitotic attempt occurs.