Tangent 1: JKR, Genetics, and Squibbery AKA Towards a Unified Theory of Homozygous Dominance in Magical Persons
The reviewer commented on this (from Chapter 4 of A Gryffindor and a Slytherin):
Obviously, Draco is slightly panicked and he has no formal education in genetics, but he has a point. You see, the wizarding world is a closed population. Once you open it up to the world at large, there is a definite risk of their unique characteristics as wizards, as it were, disappearing or changing to the point of being unrecognisable. Or is there?
If you have a pure-blood magical person mate with a Muggle, we know that the result will most likely be a magical child (e.g. Tom Riddle, Seamus Finnigan, Dean Thomas). If a Muggle-born magical person mates with a pure-blood magical person, the result will also most likely be a magical child, also (e.g. Harry Potter). We also know that it is possible for two Muggles to produce a magical child (e.g. Lily Evans, Hermione Granger, Hannah Abbott, etc ad nauseam) or even two in a row (e.g. the Creevey brothers). Two magical people will usually produce magical children, with the exception of those times when they produce Squibs. Which brings me to the next point.
A December update on jkrowling.com featured the following phrase: "Squibs are rare; magic is a dominant and resilient gene.". Cue fandom discussion and facepalming and then a proposal to stop the madness. I facepalmed right along with everyone when I read the above phrase, and I could follow those discussions without much difficulty when they got technical (owing to a limited background in theories of genetics).
In a nutshell, magic cannot possibly be a dominant gene, given what we know from canon. A dominant gene carries a dominant trait. They're called dominant because they show up. If you have a gene for brown eyes, you're damn skippy you're going to have brown eyes, even if your other gene is for blue eyes. So IF someone carries the "magic" gene AND the "magic" gene is dominant, THEN the trait carried by the "magic" gene (AKA magical ability) necessarily has to show up. That's pretty much the gist of the problem. JKR says that magic is dominant, but that means that Muggle-borns are impossible.
They have to get their magic genes from somewhere, and the only place they can get them are their parents. But if the parents have the magic gene, and the magic gene is dominant, the parents cannot by definition be Muggles (not a drop of magical blood in them). They must have the magic gene to pass on, right? And if the magic gene is dominant, then they must also manifest it -- and so we come full circle.
That, however, is pure Mendelian genetics. High school biology notwithstanding, human beings are not peas and our traits are not simply controlled by a single set of alleles (an allele is one member of a pair of genes). There is also incomplete dominance wherein there's a blending of traits that causes a third phenotype (manifestation of a gene), and codominance (where there is no real dominant or recessive allele, and both traits are expressed, e.g. the AB blood type).
It's possible that magic is the result of incomplete dominance or codominance, but my poor brain is too overworked to try and come up with possibilities for how that might be feasible. So I came up with a simpler possibility. Sickle cell anemia is caused by the presence of two incompletely recessive alleles. Why can't magic be caused by the presence of two (but not one) dominant or incompletely dominant alleles? Basically, I posit that for magic to manifest, the person in question has to have two copies of the dominant magic gene for the "trait" of magic to show up.
I theorise. I drew Punnet squares for all these, by the way. I am obsessed.
(M = magical allele; m = non-magical allele)
Magical person (MM) + Magical person (MM) = 100% chance of a magical child (MM) unless there is a mutation, and one of the Ms becomes an m. Then you have a Squib (because you need two M's to be magical). There may be other genetic influence -- Thaddeus Thurkell had seven Squib sons, it's possible that he possessed a trait that caused his M gene to become an m during meiosis and thus he could only produce Squibs despite his 100% magical genetic background.
Magical person (MM) + Muggle/Squib (Mm) = 50% chance of a magical child (MM), 50% chance of a Squib (Mm) (ETA: Thanks to imadra_blue for pointing out that a Squib has at least one magical parent).
Muggle/Squib (Mm) + Muggle/Squib (Mm) = 25% chance of a magical child (MM), 75% chance of a Muggle (Mm or mm). No Squibs here because neither of the parents are magical.
Muggle/Squib (Mm) + Muggle (mm) = 0% chance of magical child BUT 50% chance of a child who is capable of producing magical offspring with other carriers of the M gene. No Squibs here either.
Muggle (mm) + Muggle (mm) = Muggle child (mm) 100% of the time, unless there is a mutation that makes one of the m's into an M and thus the child does not manifest magic, but is capable of producing magical offspring if paired with a Muggle (Mm), a Squib (Mm), or a magical person (MM).
In the above scheme, Squibs are still rare, and the "magic" gene remains dominant.
Blood-lines are not being taken into account here, since I'm positing that in order for magic to be manifested as a trait, you have to have two copies of the "magic" gene. Pure-bloods all have two copies, but so do Muggle-borns and half-bloods. The issue of blood thus appears to be a moot point.
So to that effect, AGS!Draco does have a point about intermixing with Muggles, but Muggle-borns are not a risk to the wizarding population because they are MM and thus if they mate with other magical people (who are also MM), they run about as much risk of producing a Squib as MM pure-bloods mating. This is, of course, assuming that my theory of homozygous dominance of magic is correct.
Ahem. Moving on to next tangent, then.
Tangent 2: Death Eaters, Voldemort, Muggle versus wizard mentality
Consider that the Death Eaters' (and their sympathisers') hatred of Mudbloods is powered by ignorance (they don't realise that magical power does not become diluted by the introduction of Muggle-borns into the wizarding world) or rather simple prejudice coupled with wilful or unintentional ignorance.
Ignorance breeds hatred far too often in our (Muggle) world; I could list examples but I'm sure most of you are more than aware of what I speak. So the Death Eaters are acting from a position of threatened superiority. If my thoughts on magical genetics are correct, the issue is not one of any real superiority (since any two Muggles with the M gene present could produce a perfectly capable witch or wizard such as Lily Evans). Rather, it's an issue of perceived superiority much like some white people consider themselves inexplicably better than all black people, or vice versa. I predict that there are pseudo-scientific and -intellectual treatises amongst the pure-bloods on why Muggle-borns are a menace to wizarding society.
The view that superiority is merely perceived is strengthened by something Draco says in GoF -- he tells Harry and Ron that the Death Eaters engaging in Muggle torture are somehow capable of spotting a Mudblood. Mrs. Black's portrait correctly identifies Harry as a half-breed, which I think is based on hearsay rather than any real evidence. If the pure-bloods were so good at spotting the impure, surely they wouldn't have allowed a half-breed like Tom Riddle (who is even less pure than Harry, since Harry's mother was a Mudblood, but Tom's father was a Muggle) to lead them to wizarding glory? In OotP, Bellatrix is absolutely appalled at the notion that Lord Voldemort is not a pure-blood. I'm sure we'll hear more about this in future books, but so far the ability to "spot a Mudblood" appears to hinge on interpersonal connections rather than any innate abilities that pure-bloods aspire to.
Another thing that seems evident is that The Death Eaters (as led by Lord Voldemort) seem to operate under the old "take over the world" schema, which is predictable from LV, who grew up amongst Muggles and thus is more than likely familiar with Muggle history and culture. I posit that he has "disowned" his Muggle heritage entirely and he is more than likely to be disdainful of anything made/created by Muggles (perhaps even moreso than his pure-blood associates, which could only have contributed to his guise as a pure-blood).
Wizards don't always think like Muggles -- that much is obvious after a cursory look at the wizarding world through the eyes of a Muggle or someone who was raised by Muggles. They allow their children to play dangerous sports on broomsticks -- in our world, many children aren't even allowed to ride their bicycles without helmets and large amounts of padding. They think nothing of modifying the memories of another magical person or Muggle -- in our world (at least the parts of it that have accepted Western ethics), that would be considered a severe breach of privacy and an insult to human dignity.
My theory is that Voldemort is applying Muggle philosophy in the wizarding world. Think about it -- why haven't the wizards taken over the Muggles and made us their bitches up to now? Because they are insular, they think differently, they have different moral standards. They'd rather not associate with us at all. However, then Lord Voldemort comes along and he seems hell-bent on "taking over" the wizarding world and most likely moving on to the Muggle world after he's done there. All this "taking over" shit reeks of Muggle mentality; the wizards seem content on padding the government's pockets and gaining influence that way -- until one Tom Marvolo Riddle comes along and says:
No matter wherever you are, you're never too far
From revenue huh, cause you can be king
You can rule the world, you can do anything
It's on you baby, cause you can be a star
No matter wherever you are, you're never too far
[Lyrics from Eminem's Never 2 Far. You must admit it's amusing trying to picture rapping!Voldemort.]
...and suddenly there is a loyal following around him, wizards and witches rallying behind the idea of ... what, exactly?
It seems as though the Death Eaters are interested in cleansing their world of impurities and Muggle filth, whereas Lord Voldemort is interested in power because deep down, he cannot identify with the need for cleansing (since he is himself an impurity). But what else are the Death Eaters after?
Sure, they're in positions of power given that their almighty Lord rises to the top. So what? A lot of the Death Eaters are already in positions of power and/or influence with the Ministry, for one. Why the Dark Lord? Why Death Eaters? The most obvious answer is some hare-brained quest for immortality, but that doesn't really make sense. Nicholas Flamel was around long before Volders appeared on the horizon; those wizards who wished for immortality could have simply stolen the damn Stone from him or bought some of his Elixir, or whatever. Immortality is too convenient and it doesn't make sense given what we've been told.
Therefore, I predict that there will be a clash of wizard vs. Muggle mentality in Voldemort's camp, at some point in the two future books.
Also, while looking up a JKR-link to confirm a canon point, I stumbled across a section that I'd read before, cursively, before I was as intensely interested in Draco as I am now. Well, now that Draco has been camping out in my brain for the past 2.5 months, this totally made me do a double take.
OK. I now understand where the first scene of hackthis' Thousandth Man Verse probably came from. *facepalm* However, that is not my point. The bolded part is my point. Basically, she's saying that Draco is capable of being reasonable. That he is not so egotistical and arrogant as to view absolutely everyone as "beneath him." That purity of blood is really that important to Draco (and hence he would always see Harry as somewhat inferior). That Draco is mature enough to admit that someone is cleverer than him (perhaps this is only because Theodore is somewhat cleverer, I don't know.) But -- YES! Draco does have depth! Or perhaps this is just ... interpreted depth. Because that's exactly what AGS!Draco is like. Because I desperately hope for Draco (or any Slytherin really, but I'd prefer Draco) shown as a human being. I don't want him redeemed and turned Good, I don't want him crawling to Harry for help. I'd just like to see him as more than a two-dimensional racist bully. I'll even be happy with a three-dimensional racist bully.
Speaking of three-dimensional racist bullies, AGS!Draco is doing just fine, thank you for asking. Chapter 13 is not quite ready for beta yet because I still have to write a section that required more research than I'd bargained for.
imadra_blue translated the summary for AGS into Fangirlese. Behold:
Title: Grif n Slithy!
Author: fu-fur-fury . . . f
Summary: OMG! Liek, so Dray is like a Slithryn, rite? Adn he lieks Hairy, but he dosnt. I tink. *.*
Story: liek, Siths talk alot....OMGWTFWHERSTEHSEXX??????////? OOOOOoooo!!!!1111one!!11 AWK! ....I dun gettit. Wen tehy gone hav sexxx???!!!111one???!!! I stil dun gettit Theres liek, thinkin intihs.... @_@ Bliaze is coot. I wan te hav his babbiesss!!!!111eleventyone!!!! *brick* OMGIWUVU!!!!1111ONE!!!