Were the Creevey Brothers Muggle-Borns?

[danajsparks.livejournal.com]

We have discussed before how Rowling seems to have "forgotten" in her later books that she originally intended for Colin Creevey to be a Muggle-born student. For one, it seems somewhat improbable that Colin and Dennis both turned out to be wizards if both of their parents were Muggles. For two, the fact that Professor McGonagall had to "chivvy" at least one Creevey out of the castle in chapter 31 of DH suggests that, despite the prohibition against Muggle-borns, the brothers were able to attend Hogwarts while Tom was in power... though it's possible that Colin, like Dean, was present for the final battle only because he had responded to Neville's alert on the DA coins.

However, it occurs to me that Colin's blood status was actually a bit ambiguous from the beginning.

What he told Harry in chapter 6 of COS is this:

I never knew all the odd stuff I could do was magic till I got the letter from Hogwarts. My dad’s a milkman, he couldn’t believe it either. So I’m taking loads of pictures to send home to him.

What Colin did not include in his introduction is any information about his mother. Thus, despite Colin's ignorance of magic, it's entirely possible that his mother was, in fact, a witch (or maybe a squb). If so, she would not have been the first witch to have hidden her magical abilities from her Muggle husband for as long as possible, nor do we know if she was even still in the picture by the time Colin received his invitation to Hogwarts.

Yes, Colin was petrified by the basilisk in COS, but that does not prove that he was a Muggle-born. It's possible, for instance, that he was simply in the wrong place at the wrong time. Furthermore, as far as we know, the only way to properly identify a Muggle-born is by investigating his or her family tree, and Diary!Tom could only know what Ginny knew or believed about the current student body.

Comments

[jodel-from-aol.livejournal.com]

Well, like I say, switching off a single magical gene wouldn't be enough to produce a Squib, because nothing we've seen in canon supports the claim that magic is produced by any single gene. So Squibs are probably not due to any gene being switched off, but by some other factor that interferes with *all* of their magical genes in some manner.

I'm not a geneticist, but that sounds more like something added than something faulty which later corrects. Because the magical traits are still there or there would be no Muggle-born wizards.

[danajsparks.livejournal.com]

OK, I think I see what you're saying.

But, once you allow for magical ability to be dependent upon more than one gene, I don't think you even need something like spontaneous mutation to explain wizarding genetic patterns.

Let's suppose that magical ability is dependent upon two genes, each with two alleles.

Gene 1 Alleles: U,u U is dominant for magical ability

Gene 2 Alleles: W,w W is dominant for magical ability

There are 16 possible combinations from these two genes. Both U and W are required for magical ability, so a wizard or witch could have the genotypes UUWW, UUWw, UuWW, or UuWw. And a squib or muggle could have the genotypes UUww, Uuww, uuWW, uuWw, and uuww.

So, even though U and W are both dominant for magic, it's still possible for two magical parents to produce a non-magical child and for two non-magical parents to produce a magical child.

If the magical population were to be very diligent about "breeding out" the recessive u and w alleles (by not reproducing with squibs), then, within 9 generations or so, a pureblood witch would have a 98% chance of producing a magical child with a pureblood wizard, a 90% chance of producing a magical child with a Muggle-born wizard, and an 81% chance of producing a magical child with a Muggle.

You can view the math for this here (https://docs.google.com/spreadsheet/pub?key=0Asq6Ul6gdxBCdHVhSlZidVVjV080TEtJWTdxa2VLZ2c&gid=0) (Like I said, I've spent way too much time thinking about this)

[jodel-from-aol.livejournal.com]

You probably know more about it than I do, but yes, making the issue dependent upon two factors rather than one would explain a lot of the variables. Unless the variables are single-gene additions having little to do with magical ability, but only operative in the presence of active conduction of magical energies.

[danajsparks.livejournal.com]

Lol, no, I make no claims of expertise when it comes to this stuff. I've been working on the math on and off for months, and I'm not sure if it's even right. I just don't have a life. :p

[oryx_leucoryx]

So 'true' Muggleborns are descendants of squibs on both sides, one parent Uuww and the other uuWw. And Hermione really is related to Hector Dagworth-Granger.

But besides the two main genes there must be minor modifier loci - that in themselves can't cause one to be magical, but if one is magical some alleles of these loci cause one's magic to be exceptionally strong. That would explain Albus, Tom and Lily (and probably Severus and maybe Harry too).

[danajsparks.livejournal.com]

----So 'true' Muggleborns are descendants of squibs on both sides, one parent Uuww and the other uuWw.

Well, yes, a Muggleborn's parents are both geneticallly "squibs," but their most recent wizarding ancestors could be many, many generations back.

And I think the truth may be that everyone has at least one magical ancestor somewhere in their family tree, in much the same way that probably anyone with European ancestry is descended from British royalty (http://www.theatlantic.com/magazine/archive/2002/05/the-royal-we/2497/). But that doesn't mean that everyone is carrying around magical DNA. For instance, if a first generation squib with genotype Uuww marries a muggle with uuww, then 50% of her children will be uuww- completely "muggle."

----But besides the two main genes there must be minor modifier loci - that in themselves can't cause one to be magical, but if one is magical some alleles of these loci cause one's magic to be exceptionally strong. That would explain Albus, Tom and Lily (and probably Severus and maybe Harry too).

Actually, I think the magical strength of Albus, Tom, Lily, Severus, and Harry may have something to do with the fact that they all have recent muggle ancestors. They all have a high probability of having the genotype UuWw, especially Tom, Lily, and Severus. This suggests to me that the "recessive" alleles u and w may, in fact, carry rather valuable genetic material that has been lost over time in the pureblood population. They may be alleles that affect factors such as intelligence, metabolism, mental stability, immune system strength, etc. So I suspect that Muggle-borns and Half-bloods tend to be more powerful because of hybrid vigor.

But I agree that there are probably additional genes that play a role in magical strength and specific magical abilities. Again, they may not be genes that only affect magic. For instance, there's a genetic disorder known as Ehlers–Danlos syndrome (http://en.wikipedia.org/wiki/Ehlers%E2%80%93Danlos_syndrome) that affects collagen and causes various connective tissues to be more "elastic." So maybe a metamorphmagus is a witch with something like EDS.