Molecular Development - X Inactivation
Introduction
The presence in females of 2 X chromosome raises the issue of gene dosage, in the case of mammals this is regulated by inactivating one of the X chromosomes (see X inactivation notes). In some other species compensation occurs by increasing the expression of X in males. The pattern of which X chromosome is inactivated in cells appears to be random, generating 50% cells expressing Father X, 50% cells expressing Mother X (mosaic pattern). The theory of random X inactivation was first suggested in mice in 1961.
A second form of X inactivation that occurs only in male meiotic spermatogenesis, meiotic sex chromosome inactivation (MSCI), is not covered in these current notes. MSCI is the process of transcriptional silencing of the X and Y chromosomes. (More? Meiotic sex chromosome inactivation. Turner JM. Development. 2007 May;134(10):1823-31.)
References
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Cite this page: Hill, M.A. (2024, June 15) Embryology Molecular Development - X Inactivation. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Molecular_Development_-_X_Inactivation
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