Creevey Brothers and Genetics

[r.yoo at scotland.com]

No: HPFGUIDX 6426

Instead of the "wizarding gene" being recessive it is possible that it 
is "sex-linked".  An example of a sex-linked gene is colorblindness, 
which is found mostly in males.  This would explain why both Creevey 
brothers are wizards even though their parents are Muggles, however 
that doesn't explain Hermione.  There are women who are colorblind, 
but that is usually as a result of some other gene, not the sex-linked 
gene that causes it in males.  Not to be mean, Hermione could be the 
result of a mutation.  Do we know really how big a proportion of kids 
are from Muggle families?  Or how many are wizarding siblings from 
Muggle parents?  Is it rare?

There are probably even more complex genetic explanations, but I sort 
of zoned out half way through my semester of genetics :)

Rebecca