In the Harry Potter universe, magic must be a recessive gene

[Dorian Gray]

That's how muggles can have a magic child, and why there are so many muggles compared to magic folk.

(insert Mendel science here)

[Wowbagger]

Wizard parents can also give birth to non-magical children, in that case they are called "squibs".

[casebro]

So, what with the randomness implicated by the first two posts, perhaps there is a genetic mitochondrial component to the phenomenon? (is Heteroplasmic the term?) More than just one pair of genes, with one pair being recessive, then another genetic component that is may be recessive, dominant, or mitochondrial?

[rjh01]

No. Actually it is the interaction of several genes that create wizards. It also determines what type of wizard and your power. That is why in the muggle world you get people who can, under the right conditions perform some magic, sometimes without them realizing it.

[Ixion]

The mad scientist in me is already wondering if gene therapy can create ultimate wizards and witches!

:alien003:

[Denver]

And let's not forget the midichlorians.

[Ixion]

And let's not forget the midichlorians.

I'd rather we did.

[Dorian Gray]

the Bag is right, so there must be more than one set of genes - like how there are hazel eyes, or something.

[ImaginalDisc]

Nein. (http://en.wikipedia.org/wiki/Penetrance)

Just because you carry a gene for X does not mean you will develop X. Schizophrenia undoubtably has a strong genetic component, but not everyone who has the gene develops schizophrenia, for example. Identical twin studies bear this out.

As a counterproposal, maybe every human being in the Potter universe carries the gene(s) for magic, but factors such as magical exposure in the womb, or having a ridiculous name make you develop magical talent.

[Dorian Gray]

I'm thinking magic is more like skin color than adult onset disease.

[casebro]

Yeah Dorian, I think there are seven genes involved in skin color.

Heterogeneous might be the word.