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Author: Subject: Question about "Barr body"
Wolfram
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[*] posted on 29-12-2004 at 07:42
Question about "Barr body"


I have a question about the so called Barr body in females. X-linked recessive deseases are very uncommon in females. So how could one of the X-es be said to be constitute the "inactivate" Barr body. If one X was really inactive there would be no advantage for females to have two X-es instead of one when considering diseases like hemophilia etc. So how could one of the X be considered inactive, and yet contribute to production of functional proteins???
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[*] posted on 29-12-2004 at 09:11


Are you talking over recessive genetic illness? Hemophilia and Daltonism are recessive, as long as one of the X has the good gene it'll take over the damaged one. This is why woman with hemophilia/daltonism are harder to find, then need the two gene to be affected, men only need one since there are no equivalent on the Y gene.
Hope this help you if i understood well.
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Wolfram
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[*] posted on 29-12-2004 at 13:38


Well I have found the info myself. I was talking about the "Barr body". It turns out that womens are actually a mosaic of diffrent X-chromosomes active in diffrent cells, a fact that I was not aware of:

http://en.wikipedia.org/wiki/Barr_body

This means that monozygotic female twin are more phenotypicly diffrent from each other than male monozygotic twins since female monozygotes differ in the pattern of X-inactivation.

[Edited on 29-12-2004 by Wolfram]

[Edited on 29-12-2004 by Wolfram]
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