[HPforGrownups] Re: Muggle born magical sibs?

[Laura Ingalls Huntley]

No: HPFGUIDX 130179

Donna:
>> If Colin is muggle born so would his brother be.  Isn't
>> it a bit unusual for sibs from muggle families to be
>> magical?  If sibs from muggle families can be magical,
>> isn't it possible for Petunia to be magical, too, but just
>> reject it?  We know Petunia knows more about the ww than
>> she lets on.

Heather the Buzzard:
> I think it's possible -- if for instance, muggle-born wizards are just
> random, say 1 in a million births -- then it's highly unlikely for
> siblings to be magical.  Unlikely, but not impossible.  Colin and 
> Dennis
> would be like the lottery-winners.  Perhaps there's something important
> about them, though, that will be revealed later.

Actually, we know, per JKR's explanation, that magical ability is 
determined by genes.  Now, if magical ability is genetic (even 
funky-JKR-genetic), then that means that there must be magic genes 
floating around out there in the general Muggle population, and that 
any muggleborns are the result of these genes combining in the right 
way.  Therefore, while producing a muggleborn might be rare (two 
Muggles with the right recessive or inactive genes must bear a child, 
and that child must get the right combination of genes from its 
parents), once you already *have* a couple (i.e. Colin's parents) that 
are capable of producing a magical child, the chances of them producing 
*another* magical child are actually relatively quite good .

Laura (who apologizes for the absolutely convoluted way that was 
explained and hopes everyone could follow.)