XPost: alt.fan.heinlein   
   From: wthyde1953@gmail.com   
      
   Lawrence D’Oliveiro wrote:   
   > On Sun, 15 Feb 2026 15:52:31 -0500, William Hyde wrote:   
   >   
   >> Male sufferers cannot pass hemophilia onto their sons, as the son's   
   >> x chromosome must come from the mother. On the other hand their   
   >> daughters are always carriers (unless they suffer from Turner   
   >> Syndrome, I suppose).   
   >   
   > There is only one functional gene on the human Y-chromosome, which is   
   > why it’s so tiny.   
      
   There's not enough evolutionary pressure to select against damage to   
   genes on the Y chromosome that are also on the X.  Thus most of it is   
   inactive, barring those  genes that produce males.  If it only contained   
   the sites that are actually active it would be tiny, but as there is a   
   mass of non-coding material it is not.   
      
      
   William Hyde   
      
   --- SoupGate-Win32 v1.05   
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