[HN Gopher] Xist ribonucleoproteins promote female sex-biased au...
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       Xist ribonucleoproteins promote female sex-biased autoimmunity
        
       Author : PaulHoule
       Score  : 26 points
       Date   : 2024-02-10 17:42 UTC (5 hours ago)
        
 (HTM) web link (www.cell.com)
 (TXT) w3m dump (www.cell.com)
        
       | echelon wrote:
       | Females are XX and double dosage of the X chromosome genes is
       | fatal. One of the copies must be deactivated.
       | 
       | Double dosage of any chromosome in humans is typically not
       | compatible with life or will cause severe mental and
       | developmental dysfunction. The body and its development are fine
       | tuned for the gene doses it receives.
       | 
       | In order for females to be healthy, the double X system evolved
       | to self-deactivate the second X chromosome so a double dosage
       | does not occur. The resulting inactive X chromosome is termed a
       | barr body. You can also see this effect in female calico cats -
       | the fur patterns are the result of some cells having one X active
       | and other cells having the other one.
       | 
       | This paper states that the gene regulatory mechanisms that shut
       | down the second X chromosome are the causal agent for this
       | differential sex determined auto-immunity. Though the X
       | deactivation mechanisms play a critical role, they can
       | accidentally trigger the immune system to attack self.
        
         | arghwhat wrote:
         | This behavior is also a cause of tetrachromacy in females: A
         | mutation in a color receptor gene in one X chromosome only ends
         | up affecting roughly half of the receptors of that type.
         | 
         | The population of that receptor is then split between mutated
         | and non-mutated, making the person sensitive to both the
         | original wavelength (but less so) and a new wavelength, giving
         | them four primaries and enhanced color separation -
         | tetrachromacy.
         | 
         | Even if the mutation is broken, they retain trichomacy - just
         | with reduced light sensitivity. This is why women color
         | blindness is rare, while men has no such backup.
        
         | lazide wrote:
         | Notably, one of the few non-serious duplication types is 47,XYY
         | 
         | [https://medlineplus.gov/genetics/condition/47xyy-
         | syndrome/#:....]
         | 
         | It tends to just make folks a little taller than they otherwise
         | would (plus a small additional chance of ADHD/ASD).
         | 
         | Weird eh?
        
         | nealabq wrote:
         | Turner syndrome happens when one of the X chromosomes is
         | missing. The result in humans is a short female who may have
         | some heart issues and may be sterile. At least according to the
         | woman I know who has it.
         | 
         | As in men, the single X-chromosome doesn't deactivate.
         | 
         | I'm curious how single-X manifests in other mammals. And if
         | Turner has autoimmune implications.
         | 
         | https://www.mayoclinic.org/diseases-conditions/turner-syndro...
        
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       (page generated 2024-02-10 23:01 UTC)