page_title: Endoreduplication
section_title: Endoreplication, endomitosis and polytenization
hierarchical_section_title: Endoreduplication / Endoreplication, endomitosis and polytenization
caption_attribution_description: English: My attempt to illustrate the subtle mechanistic differences between endocycling and endomitosis
context_page_description: Endoreduplication is replication of the nuclear genome in the absence of mitosis, which leads to elevated nuclear gene content and polyploidy. Endoreplication can be understood simply as a variant form of the mitotic cell cycle in which mitosis is circumvented entirely, due to modulation of cyclin-dependent kinase activity. Examples of endoreplication characterized in arthropod, mammalian, and plant species suggest that it is a universal developmental mechanism responsible for the differentiation and morphogenesis of cell types that fulfill an array of biological functions. While endoreplication is often limited to specific cell types in animals, it is considerably more widespread in plants, such that polyploidy can be detected in the majority of plant tissues.
context_section_description: Endoreplication, endomitosis and polytenization are three somewhat different processes resulting in polyploidization of a cell in a regulated manner. In endoreplication cells skip M phase completely, resulting in a mononucleated polyploid cell. Endomitosis is a type of cell cycle variation where mitosis is initiated, but some of the processes are not completed. Depending on how far the cell progresses through mitosis, this will give rise to a mononucleated or binucleated polyploid cell. Polytenization arises with under- or overamplification of some genomic regions, creating polytene chromosomes.
caption: Endocycling vs. endomitosis
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