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Spreading of X-chromosome inactivation

Part 1. Genetics

1.3. Epigenetics

Short Specialist Review

  1. Jason O. Brant,
  2. Thomas P. Yang

Published Online: 15 NOV 2005

DOI: 10.1002/047001153X.g103325

Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics

Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics

How to Cite

Brant, J. O. and Yang, T. P. 2005. Spreading of X-chromosome inactivation. Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics. 1:1.3:40.

Author Information

  1. University of Florida College of Medicine, Gainesville, FL, USA

Publication History

  1. Published Online: 15 NOV 2005


X-chromosome inactivation (XCI) in mammals has evolved to functionally compensate for the apparent dosage imbalance of X-linked genes between males and females. XCI is believed to occur in three stages: initiation, spreading, and maintenance; the mechanism by which inactivation spreads from the X-inactivation center is perhaps the least understood of these processes. Analysis of X;autosome translocations indicate that the inactivation of genes on the inactive X (Xi) is capable of spreading into translocated autosomal DNA, although in a more discontinuous and variable fashion, suggesting that there are X chromosome–specific features that may facilitate efficient spreading of inactivation on the X. Recent studies have shown a strong correlation between certain repetitive DNA elements and the spreading of XCI, suggesting that these sequences may, in conjunction with Xist RNA, mediate the spreading of XCI. This review will discuss the current state of knowledge regarding the spreading mechanism of XCI.


  • X-chromosome inactivation;
  • spreading of inactivation;
  • L1 elements;
  • Xist;
  • translocation;
  • chromatin remodeling