Magic and genetics (wasRe: The Mauraders' Generation)

[Hannah]

No: HPFGUIDX 123628


> Nicky Joe wonders:
> I would really like to have some explanation from JKR about the 
> genetics behind all this - some Muggles can have witch/wizard kids 
> and some witch/wizards can have squib kids.  Where is the logic?  
>  
> Arynn explained:
<snip>
> Maybe wizards have a similar getetic coding. W/m (wizard/muggle) 
and m/m (muggle squared), so even if most of the family is W/m a m/m 
could come along. Since we know squibs are WAY rarer than 
muggleborns, obviously the wizard gene is dominant. So alot of 
muggles must have latent Wizard genes.


Hannah:  Nice explanation of genetics Arynn!  JKR said that the 
magic gene is a very strong dominant gene - which works fine for the 
squibs side of it, as explained above.  Unfortunately, it doesn't 
account for the Muggle-born wizards and witches.  If a gene is 
dominant, then the parent carrying it would have to have magical 
ability as well.  

So I guess we have to assume that the Muggle-born wizards/witches 
are the result of a new mutation in the 'magic' gene.  As most half-
bloods are magical, it wouldn't make sense for the gene to be 
recessive.  Of course, there's also the possibility of multiple 
genes being involved, or of imprinting... or just that 
it's 'magic.'  I find the genetics of magic one of things in HP that 
it's better not to think about too much!

Hannah