Biology:Macronucleus

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Short description: A type of nucleus in ciliates, involved in non-reproductive cell functions

A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates. Macronuclei are polyploid and undergo direct division without mitosis. It controls the non-reproductive cell functions, such as metabolism. During conjugation, the macronucleus disintegrates, and a new one is formed by karyogamy of the micronuclei.

Macronuclei contain hundreds to thousands of chromosomes, each present in many copies.[1][2] There is no mechanism to precisely partition this complex genome equally during nuclear division; thus, how the cell manages to maintain a balanced genome after generations of divisions is unknown.

See also

References

  1. "DNA rearrangements directed by non-coding RNAs in ciliates". Wiley Interdisciplinary Reviews: RNA 1 (3): 376–87. 2010-07-15. doi:10.1002/wrna.34. PMID 21956937. 
  2. Pevsner, Jonathan (August 2015) (in en). Bioinformatics and Functional Genomics. John Wiley & Sons. ISBN 978-1-118-58176-6. https://books.google.com/books?id=OaRjCgAAQBAJ&pg=PA900. 

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