Sharing Blood/genetic theory

[jodel at aol.com]

No: HPFGUIDX 46746

"Jess" states;

<< [...I've always assumed that some muggleborns may be the products of 
bloodlines where magic was thought to have 'died out', i.e. marriage between 
squibs & nonmagic folks (For whatever reason I think of 'magical abilities' 
as a sort of recessive trait, though many of the half & half students at 
Hogwarts defy that theory, unless of course their muggle parent carries the 
recessive magic gene.)] >>

I suspect that in Rowling's world about half of the British population 
probably carry at least 1 or 2 resessive magical genes. And that you need at 
least 8 to 10 magical genes before the individual is psychicly "active" 
enough to actually do magic. I also agree that most, if not all, magical 
genes are probably resessives. For one thing, a recessive can hang around for 
aeons without ever actually being lost, and for another, they can "hide" very 
quickly in the presence of competing dominanants. It also means that once a 
pairing has produced one functionally "magical" child, it is all the more 
likely to produce others (like the Creevys, one of whose parents, if not 
both, probably just missed being magical themselves.) 

I also suspect that there is a fairly broad range of magical genes (a couple 
of dozen at least) and that not only do many wizards and witches have FAR 
more than the minimum, but that not every wizard or witch in Britian has 
quite the same set. (Which would explain how some wizard-Muggle crosses 
consistently produce magical children even if the Muggle parent may be one of 
the half of the population without any magical genes to contribute, while the 
rare wizard-witch pairing occasionally manages to produce a Squib. Although 
in the case of Squibs, there is also the possibility of gene mutation 
(possibly due to exposure to dangerous magical processes) having damaged one 
or more of the crutial magical genes, rendering them inactive.

-JOdel