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Amitosis is a term for describing a type of direct eukaryotic cell division differing from that of mitosis, the most common type of cell division. During the stages of this cell division, the nuclear membrane is not broken down as most scientists would have expected. (2) There are two stages to this process karyokinesis and cytokinesis. During karyokinesis, the nucleus is divided, which begins from constriction in the middle of the nucleus, eventually separating into two halves. Cytokinesis is the splitting of the cytoplasm of the cell, following the same process of karyokinesis.Amitosis involves a type of nuclear division that does not involve the condensation of chromatin into chromosomes and no spindle differentiation. This type of cell division is commonly seen in organisms such as amoebae, ciliates, sponges, tissues of vascular plants, arthropods, mammals, and dinoflagellates. (2) One of the major problems with amitosis is that it is an irreversible type of cell division, leaving daughter cells unable to reproduce. The mechanism of amitosis is different from mitosis due to the things previously mentioned. In 1967 Shen discovered that amitosis occurs in a pattern. Later in 1991, Maszewski determined that these cells divide symmetrically. (2) This contributes to the fact that daughter cells contain equally distributed amounts of chromatin. (1) It is a consensus opinion of today's cell biologists that amitosis as a type of cell division does not exist, but many teaching and popular sources still present it, although it is not a topic that receives much attention. Some biologists believe that the microscopic picture of splitting nuclei and cell bodies of degenerating cells corresponds not to division but to apoptosis, a type of cell death.

Bibliography

Vouilloud, Amelia A., et al. “Amitosis, Including Nucleolar Behaviour during Fragmentation, in Both Axial and Corticating Cells of Chara Contraria (Charales, Charophyta).” Phycologia, vol. 46, no. 2, Mar. 2007, pp. 178–186. Academic Search Complete, EBSCOhost, doi:10.2216/06-38.1. Accessed 2 Nov. 2017.

Magalhaes, Maria, et al. “Amitosis in Human Adrenal Cells.” Histology and Histopathology, 5 Dec. 1990.

Pfitzer, P. “Amitosis: a Historical Misinterpretation?” US National Library of Medicine National Institutes of Health, www.ncbi.nlm.nih.gov/pubmed/7433237.