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Science  29 May 2009:
Vol. 324, Issue 5931, pp. 1119
DOI: 10.1126/science.324_1119c

Cell division in the parasitic protozoan Entamoeba histolytica is an olio of polyploidy, multiple nuclei, and failed cell division. In the latest of a series of studies, Mukherjee et al. show that multiple genome complements arise because the amoeba lacks the regulatory components present in higher eukaryotes that not only control the structure of the microtubule organizing centers but also couple cytokinesis with nuclear division. The result in Entamoeba is the formation of multipolar spindles, which segregate multiple copies of the chromosomes simultaneously into unequal daughter cells. This phenomenon can be observed both in vitro and within the intestine, and there does not appear to be strong selective pressure to constrain genomic exuberance, possibly because having such lax controls is an advantage for a parasite that may encounter sudden shifts in its environment.

PLoS Negl. Trop. Dis. 3, 3409 (2009).

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