Going purely by canon evidence, disregarding Harry and Draco’s results, I would have inferred that magic was dominant, not recessive.
I assume that the magical population of Britain is much smaller than its nonmagical population, that the vast majority of magical children in Britain attend Hogwarts, and that the vast majority of Hogwarts students are British.
There are roughly a million 11-year-old Muggles in Britain. The number of Muggle-born witches and wizards in any given year at Hogwarts is counted in the dozens, at most. This puts the probability of any given child of nonmagical parents being magical at somewhere around 10^-8, which is plausible for a simple random mutation.
Wizard-born Muggles, on the other hand, are common enough that the word “Squib” was created to describe them. The level of understanding of genetics that Harry displays—the level that Draco could have if he was paying attention, even—is sufficient to realize that the frequency of Wizard-born Muggles falsifies the model they settled on.
What simple model describes both the canon evidence and the MOR!canon evidence (Harry and Draco’s results)? The best I’ve come up with so far is “Eliezer falsified data to suit his preconceptions”, which is distinctly unsatisfying. (This model will be verified if Chapter 23 is edited to make the percentage of Squib-born Wizards 75% rather than 25%, and it will be falsified if Harry and Draco eventually realize that their theory doesn’t work.)
According to Eliezer, the “muggle-born” are in fact the children of people who have one copy of the magical gene (and thus are descendants of Squibs who were cast into muggle society.). That only one in ten thousand people in Britain (who are not wizards themselves) have a copy of the gene for magic is not that improbable.
Does MOR explicitly mention there being wizard-born squibs? Because it seems to me that it’s impossible for there to be muggle/squib-born wizards, there to be wizard-born squibs, and for magic being a single gene trait all at the same time.
That is, unless that gene behaves in a way that ordinary genes do not. For example, there could be a spell which de-magicks gametes—either as a curse, or as an unnoticed side effect. That would explain both the existence of wizard-born squibs and the shrinking population of magic users, without affecting the fraction of squib-born wizards.
I don’t think MOR explicitly mentions wizard-born squibs, but the original HP canon defines “squib” as a nonmagical child of magical parents. The existence of the word implies a certain minimum frequency of the phenomenon. I assume anything true in canon is true in MOR unless explicitly contradicted.
I, too, originally thought that it couldn’t be a single gene trait, for exactly the reason you mention, until I realized just how rare muggle-born wizards were.
Other models have been proposed in the fanfiction.net comment thread. For example, there could be two gene traits, one controlling witch/wizard/squib vs. muggle with muggle dominant, and one controlling squib/muggle vs. witch/wizard with squib/muggle recessive. The parents of Muggle-borns would be carriers of the recessive not-a-muggle gene, and the parents of Squibs would be carriers of the recessive squib gene. (Note, though, that this still doesn’t explain Harry and Draco’s results.)
Because magic can have arbitrary effects, I prefer to assume nonmagical explanations wherever possible. Admitting magic essentially removes the possibility of being surprised by any observations.
There was some discussion of genetics in the FF.net comments for Chapter 23; I’d like to continue that here.
Going purely by canon evidence, disregarding Harry and Draco’s results, I would have inferred that magic was dominant, not recessive.
I assume that the magical population of Britain is much smaller than its nonmagical population, that the vast majority of magical children in Britain attend Hogwarts, and that the vast majority of Hogwarts students are British.
There are roughly a million 11-year-old Muggles in Britain. The number of Muggle-born witches and wizards in any given year at Hogwarts is counted in the dozens, at most. This puts the probability of any given child of nonmagical parents being magical at somewhere around 10^-8, which is plausible for a simple random mutation.
Wizard-born Muggles, on the other hand, are common enough that the word “Squib” was created to describe them. The level of understanding of genetics that Harry displays—the level that Draco could have if he was paying attention, even—is sufficient to realize that the frequency of Wizard-born Muggles falsifies the model they settled on.
What simple model describes both the canon evidence and the MOR!canon evidence (Harry and Draco’s results)? The best I’ve come up with so far is “Eliezer falsified data to suit his preconceptions”, which is distinctly unsatisfying. (This model will be verified if Chapter 23 is edited to make the percentage of Squib-born Wizards 75% rather than 25%, and it will be falsified if Harry and Draco eventually realize that their theory doesn’t work.)
According to Eliezer, the “muggle-born” are in fact the children of people who have one copy of the magical gene (and thus are descendants of Squibs who were cast into muggle society.). That only one in ten thousand people in Britain (who are not wizards themselves) have a copy of the gene for magic is not that improbable.
Are you sure that’s actually from Eliezer directly? I thought that was just the theory that Eliezer had Harry and Draco settle on.
ETA: Also, it’s more like one in one hundred thousand.
Does MOR explicitly mention there being wizard-born squibs? Because it seems to me that it’s impossible for there to be muggle/squib-born wizards, there to be wizard-born squibs, and for magic being a single gene trait all at the same time.
That is, unless that gene behaves in a way that ordinary genes do not. For example, there could be a spell which de-magicks gametes—either as a curse, or as an unnoticed side effect. That would explain both the existence of wizard-born squibs and the shrinking population of magic users, without affecting the fraction of squib-born wizards.
I don’t think MOR explicitly mentions wizard-born squibs, but the original HP canon defines “squib” as a nonmagical child of magical parents. The existence of the word implies a certain minimum frequency of the phenomenon. I assume anything true in canon is true in MOR unless explicitly contradicted.
I, too, originally thought that it couldn’t be a single gene trait, for exactly the reason you mention, until I realized just how rare muggle-born wizards were.
Other models have been proposed in the fanfiction.net comment thread. For example, there could be two gene traits, one controlling witch/wizard/squib vs. muggle with muggle dominant, and one controlling squib/muggle vs. witch/wizard with squib/muggle recessive. The parents of Muggle-borns would be carriers of the recessive not-a-muggle gene, and the parents of Squibs would be carriers of the recessive squib gene. (Note, though, that this still doesn’t explain Harry and Draco’s results.)
Because magic can have arbitrary effects, I prefer to assume nonmagical explanations wherever possible. Admitting magic essentially removes the possibility of being surprised by any observations.