Regardless of whatever shit JKR spews, the terms of magic she has set out are not congruent with standard genetics. You can't reconcile Muggleborns, Squibs and the way inheritance seems to pass.

There is also the politically correct observation she regularly makes that the half-bloods and muggleborns are often more magically talented than purebloods that further blows up the genetics idea.

 

Why would a Half-Blood or Muggleborn being more talented "blow up" the genetics idea? There's nothing in the genetics that says that the longer the gene has been in your family, the better a wizard you will be. Once you have the gene, you have it, no different to anyone else, and it's down to your skill how talented you are.

It makes sense though that Muggleborns would have more skill on average, as they'll be far more fascinated by magic, not having grown up with it, and thus will study it harder, increasing their skill.

 

I also remember from high school weird mechanisms that would let a DNA strand to transfer to another chromosome during cellular multiplication, or something like that. Does anybody else know something about that, or is my memory playing triks on me? In any case the point is, as none of the simple cases explain HP demographics well, more you would have to dwell into more complicated case to find a fully satisfactory theory, rather than a very patched up one we have developped on the concept of a recessive magic gene.

Of course, if in the case of a recessive magic gene we attribute squibs to magic, we can do the same for Muggle-borns in the case of a dominant magic gene - say in the same way the DADA job is cursed at Hogwarts, a spell to make the gene appear in Muggles more often than normal through mutation. The idea I like the least about this is that it gives scientific backing to pureblood supremacists, which is inherently contrary to the moral ideals of canon.

 

Crossing over at the chiasmata during meiosis (where the cell splits from diploid to haploid - 1 cell to 4) which occurs in the testes and ovaries. Basically, when the chromosomes are lining up along the center of the cell in preparation for cell division, a chiasmata may form, crossing two chromosomes together, and they switch a strand of DNA. Leads to greater genetic variation in offspring. I can't think how it would affect HP genetics though. Tinn or Sree would be able to say better, since I'm relying on just my A-Level Biology here.

It's less convenient this way around though, as there are far more Muggleborns than there are Squibs.

 

When there are only one dominant and one recessive allele to a gene, the gene becomes like a switch: on or off. Muggle-borns are just as much 'on' as pure-bloods.

Thanks; I really didn't pay attention during biology class, but that's what i was talking about. But you're right, I think it was only crossing, it wouldn't allow the allele to magically appear on both genes.

There are more Muggle-borns than squibs because Muggles produce more offspring per unit of time than wizards. I think that JKR intended for the probability of both to be the same in a particular case of mating. Although I stand by the first statement for the sake of symmetry, I actually think there are quite a lot of squibs. I can think of at least three, which is quite a lot considering that I can count the Muggle-borns I can think of on my two hands, and that the events of DH made them all stand out, contrary to squibs a lot of whom I suspect just blend into muggle society.

Edit: I know there are a lot more than ten Muggle-borns that appear in canon, but without peeking at hp-lexicon I couln't think of them.

It would make some sense (though a lot of people are hardworking without being fascinated by their subject), but I don't think Muggle-borns being better is actually canon. I think she describes an equality in ability. I've actually decided to call it magical intelligence, because I think it's the ability to learn and master (and remember) magic, and it should be differentiated from normal intelligence because they are related but not equivalent.

 

But this isn't borne out by canon. There are wizards like Voldemort and Dumbledore who are capable of vastly greater feats of magic than their peers, even before they know "magic" even exists. Conversely there are wizards who are barely better than squibs.

If there are degrees of magical strength then wizard+wizard pairings would conceivably produce stronger offspring on average than wizard+muggle or muggle+muggle (just like breeding dogs for desired traits). This also isn't the case in canon, so I'll just go with "internal inconsistency".

 

All of which can be put down to magical skill.

Even if there was raw magical strength, there's no reason to think it would be genetic.

I think at some point JKR has said that Muggleborns account for 25% of wizarding population, so a lot of the wizards we know will be Muggleborn without us knowing.

 

Well, I need someone who's excellent at biology and what not to help me with a plot device in my story. I hate it when people use science in a story and it doesn't make sense, so I'm just going to scrap the idea entirely unless I can get some help.

If you want to help, and have a deep understanding of biology, contact me via PM from ff.net.
​

 

Whether or not you call it "skill" or "power" is irrelevant, it's whether or not it is genetic that matters (from the perspective of pureblood supremacy). Given that Tom Riddle's high level of "skill" was already manifested as a young child in an orphanage despite having no knowledge of magic or wizards, it strongly points to an inborn rather than environmental factor.

 

For Tom Riddle it can be explained through character and situation: he needs to be special, different, and to control others. Frustration would bring out the accidental magic, his desire to be different would lead him to explain it as something special (as opposed to Harry who is rather subjugated), and his 'magical intelligence' would allow him to understand it and nurture his talents better. Nowhere in the explanation do you need to bring in magical power. The greatest part about this theory is that if 'magical intelligence' is transfered genetically in the same way as normal intelligence seems to be (it is hard to prove, but I think the accepted view is that there is a genetic influence, as well as education), then Muggles could have and transfer 'magical intelligence' genetically without using it.

 

Not really. There are plenty of Half-Bloods like Tom that are far less skilled. There are plenty of Purebloods less skilled. There are plenty of Muggleborns less skilled. This is because pretty much everyone is less skilled than Tom Riddle, because he is a magical prodigy.

Tom Riddle's success at magic at an early age had nothing to do with his ancestors and everything to do with the fact that he was a very intelligent, creative young man with a natural instinct for magical thinking (just as one can have a natural predisposition towards maths, or languages), who believed that he was special, was able to use his emotions to manipulate his accidental magic and was in a situation in which these factors flourished and because needed/useful.

 

Yes, but if there is an genetic implication in the appearance of 'magical skill/intelligence/power' it can be independent from one that determines whether the magic is actually there.

If you want to take it one step further though, there is a distinction you can make, that relates to the breeding comment you made. If you take the theory of evolution as a model (which I do), then over time (and until recently- refer to the film 'Idiocracy') the species improves itself by the fact that the better specimens statistically reproduce more than the lesser specimens. Let us assume that there is a gene for magical power/skill/intelligence. Then, for a wizard or witch, that would represent an evolutionary advantage - he is more likely to reproduce because he is more likely to live to reproduce, and a member of the opposite sex will intuitively recognise this advantage. However, if a Muggle had great magical skill/power/intelligence without actually having any magic, this normally wouldn't be of any advantage.

The counter-argument for this is, if you conceive magical intelligence to be related to normal intelligence, as I do, then it would be so genetically as well, and as intelligence is an evolutionary advantage it would allow magical intelligence to develop unnoticed.

Of course, the ways of modern society make it so that the theory of evolution really doesn't work very well. In the muggle world, the ones who have the best means of supporting children are the ones who have the less children. In the wizarding world, the most skilled wizards seem intent on killing each other. In any case, now people often end up mating with 'equals': the most genetically disadvantaged people can perfectly have children as long as they find somebody at an equal disadvantage to have them with.

 

If we are to go by the belief that magic is outside the purview of science wouldn't the 'gene theory' end up having to be scrapped? An attempt to explain magic through science would in that case be like trying to explain Celestial Mechanics using Quantum Physics...it wouldn't work.

 

On the the terminology debate, I think the difference between skill and power is that skill puts the advanced feat of magic down to technical ability, whereas power is understood to relate to an energy output (whether in a car or an electrical system, that is what it means) and that leads to the DLP contested idea that magic would be a pool of water that you can drain, and where you have a steady input. Why I refer to intelligence is that the expression 'skilled wizard' entails that the person is actually techincally able, whereas a person could theoretically be intelligent qithout being knowledgeable.

Except it is JKR's initiative, and we don't have to explain how the magic truely works, we can simply try to explain why some people can do it and some not.

But several events in the book lead us to discovering some. Even if there are 25% (that seems a lot, I can only think of two in Harry's year), and even if you take Hogwarts to represent 5% of Britain's wizarding population (not much, for a 7 year slice) and make it 400 strong (there are 8 Gryffindors in Harry's year, multiply by 4 then 7, that gives you a 224 estimate), that's still only 8000 British wizards, out of a total British population of 60 million. 2000 Muggle-borns out of 60 million is 1/30,000 while 3 squibs out of 8000 wizards (even though those 8000 don't all mate between themselves) is close to 1/3000, which makes squibs 10x more probable than a Muggle born. This estimate is hugely exaggerated in favor of Muggle-borns (it should probably be closer to 100x), and still shows squibs to be statistically a lot less rare than Muggle-borns.

 

True enough...
Damn why did she have to go spoil our fun? Dominant and recessive gene she said, right? Is being both at the same time even possible?

If I am understanding you right, skill and knowledge are closely related...after all technical ability cannot come without knowledge. So a magically intelligent person is one who has an intuitive/logical grasp of magic that allows him to wield it efficiently without having much of a knowledge base?

That is a very interesting point. So, by today's standards, a child with a genetic disadvantage has a greater possibility of being born? And by the same token, if muggles are regarded as genetically disadvantaged, then is the fact that the muggle population grows exponentially faster than wizarding population, proof of this fact?

 

I don't think we're trying to explain the existance of magic, but rather, how it continued to exist. I want there to be a scientific explanation for the existence of muggleborns and squibs, as well as an explanation as to how 'magic' is inherited.

If muggles don't carry a 'magic' gene, then there'd be no such thing as muggleborns. So, either muggles carry some sort of gene that can trigger magical children, or it has nothing to do with genetics whatsoever.

I have a theory I want to put in my story that will play somewhat of a major part in it, but I'll keep it to myself for the time being.

 

She said 'dominant and resilient', not recessive. Resilient isn't genetic terminology as far as I'm concerned, she meant it to highlight dominant (pairs of adjectives sound better). Litterally resilient means 'tending to recover from or adjust easily to misfortune or change' which is pretty irrelevant here.

 

Ah that explains it...my mistake. Apologies.

 

Voldemort has to be a real genius to be able to do what he does at such a young age; Hermione is very smart, but as far as we know she can't do the same thing; Lily Potter is an exceptional witch, and controls flowers for fun (wandless magic Taure). These people have an intuitive grasp, but they are also very good at mastering formal spells. Magical intelligence relates to both.

Skill is the knowledge of what to perform and the ability to do it.

We don't understand wizarding society too well; however, the muggle and magical societies are essentially seperate, therefore it doesn't apply to my point, which relates to individuals inside one society.

 

I would like to point out that most genetic traits are not governed by a single set of alleles. Often many different combinations of alleles all with their own particular dominant and recessive relationships will contribute in various ways to the emergence of these traits. For something such as magic it would not be outlandish for there to be a large number of genetic prerequisites for magic to appear. This is known as polygenic predisposition and occurs for many genetically acquired traits. Presuming there are 50 'marker' genes predisposing someone to be magical and it is necessary for you to have 30 of these genes for the switch to be flicked so to speak it is easy to explain the emergence of squibs and muggleborns. For example if both the Creevey parents have a different 25 of these coders each then there are good odds that their offspring would be magical. Assuming on average each allele is no more likely to be magical than not then there would be a 40% chance of each child beng magical and therefore the probability of two magical children would be 16%.
In a way the dominant and resilient comment as applied to the trait of magic is evidenced by the large amount of muggleborns in comparison to squibs. However, this would suggest that the magical world would be growing exponentially over time and this is not shown in the fact that there was one magical school in Britain 1000 years ago and still only one today. I feel its more likely that its an answer which was only half thought through by JKR.
BTW I'm by no means an expert on genetics so if I'm incorrect feel free to criticise.