Basic Genetic Theory (Mundane Style, much, much simplified):

Our current understanding of the inheritance of physical traits is that it is dependent upon those microscopic fragments of DNA which form the genes which combine to form the chromosomes which exist in the nucleus of every living cell.

These chromosomes provide the “code” that forms the template that the body follows in reproducing each individual cell as it dies off and is replaced with a new one. With sufficiently high magnification, science has identified various recognizable examples of genes according to their position in the chromosomes, and can determine something of their behavior in the manner of their interaction with each other.

The Real World human genome consists of 23 pairs of chromosomes each of which contains strings of genes. Since the chromosomes come in pairs, the individual genes on a chromosome are each characteristically “paired” with a counterpart in the “partner” chromosome. Which is to say, another gene which occupies the same position in the partner “chain” that it occupies in its own. These paired genes interact to produce the instructions as to what qualities are to be exhibited by each newly-reproduced cell.

The basic forms of interactive behavior between these pairs of genes are:

Dominant, in which one gene, if present, will always override the building instructions of its partner;

Recessive, which allows its instructions to be overridden, but when paired with a gene whose instructions matches its own will execute those instructions, and;

Multifactoral, in which both genes contribute their instructions to the final result, which is a combination of, or a compromise between, the two.

Probably the most familiar example for demonstrating all three types of gene behavior in action is the standard textbook illustration of the inheritance of four basic human blood types. You may have already met with this in school. But if not, here it is (or here it is again) for reference.

The four basic human blood types are; Type A, Type B, Type AB and Type O.

If the gene for Type A, which is classified as a Dominant, is paired with a gene for Type O, which is a Recessive, the subject will be born with Type A blood. The Dominant Type A gene has overridden the instructions of the Recessive Type O gene.

The same is true with the gene for Type B. If it is paired with the gene for Type O, the Dominant Type B gene overrides the Recessive Type O and the subject will be born with Type B blood.

The gene for Type O is Recessive. Only if both of a subject’s genes are for Type O will the subject be born with Type O blood. With two Recessive genes there is no counter to either one’s basic instructions.

However; if you put the ordinarily Dominant genes for Type A and Type B together, neither will give way and their behavior is Multifactoral. Those subjects will be born with the AB blood type. Neither gene allows its instructions to be overridden, so the result is that both sets of instructions are followed.

Recessive genes can be difficult to trace. Short of knowing the family history, or examining the actual genes under a high-power microscope, there will be no indication whether a subject born with blood Type A is carrying two, or only one gene for Type A blood. Consequently the recessive gene for Type O may be passed along for generations without any indication of its presence in any of the people who have inherited it and passed it on.

This is the basic pattern for the principles of gene dominance. There are many additional modifying factors which I have not touched upon.

In some comparatively rare cases, the question of whether or not a gene becomes active can depend on where it sits on which chromosome. The 23rd pair of chromosomes in the human genome are not a perfect match. Whereas in females, both of these chromosomes are the same length, in males, they are not.

This means that, in males, any gene that is positioned in the portion of the longer chromosome of this pair which does not have a match — because that whole portion of the corresponding chromosome is missing — may activate independently. Such genes activate independently because there is no partner gene to contradict its instructions. These genes are referred to as being “sex-linked”, because their instructions typically only manifest in subjects of one sex, which is generally to say, men.

In the popular understanding of sex-linked genes few of such genes are beneficial. Red-green color-blindness is probably the most widely known condition related to a sex-linked gene. While it is theoretically possible for the condition to occur in females, the actual incidence of it doing so is rare. The overwhelming majority of the people diagnosed with this condition are male. It is theoretically possible that there are magical traits which may also be sex-linked, but we have yet to be told of any. Magical conductivity itself is clearly not sex-linked.

• • • •

In addition to this, there are genes that are spontaneous mutations. Some of these are not that uncommon, and are relatively harmless, such as the one in which the subject is born with eyes of two different colors, say, one brown and one blue eye. It is not altogether impossible that the basic ability to express Magic is a mutation of this type. But I am inclined to doubt it. Such mutations do not usually breed as “true” as the expression of Magic appears to. However, I will be returning to this issue for a closer look as we get further into the various ramifications.

• • • •

The first piece of awkwardness we theorists had to juggle was that in December 2004 Rowling stated in her website update that Magic is a Dominant gene. This presented us with a considerable problem.

Because, from what we had observed to date in canon (and since), this simply cannot be the case. What appeared to be more likely is that the traits which relate to magical qualities are passed along in the manner of Recessives, but that they interrelate with each other Multifactorily. Or — and far more probably — that wherever a magical gene is located in a chromosome, it is likely to activate independently — as if it were sex-linked — because there is no known opposing gene to contradict its instructions. (Below you will find an addenda to this essay which, with more recent discoveries in genetic science to back it up, postulates that this may indeed be the case.)

Ms Rowling appears to have either had this pointed out to her, or to have changed her mind, since in at least one of the flurry of post-DHs interviews, she stated that most Muggle-borns have wizards far back in their ancestry — which, if true, would go a very long way toward verifying that the “Magical” gene is indeed a Recessive.

At the same time, it also seems vanishingly unlikely that the inheritance of magic — as Ms Rowling has depicted it in canon — could ever be dependent upon any one, single gene. Or, for that mater, that magical inheritance can be *confined* to a single gene, since we have already been told that there are various magical gifts which are exceedingly rare even among wizards, and yet these gifts are shown or implied to occur within specific families, and to be passed down by the laws of inheritance just like eye color, or magic itself.

Unless genetic science itself operates in a very different manner in the Potterverse from the way it does in the Real World. To claim, as Rowling once did, that Magic is a single Dominant gene would be rather on the order of claiming that in the Potterverse, the sun sets in the South. (And that if by chance it does, then it must do so for Muggles as well as for wizards.)

• • • •

ADDENDA: Some second thoughts, circa 2009, August:

It occurs to me that perhaps this whole particular train of thought might be pushed a bit further down its track.

I hadn’t re-examined this issue for some years, but I really ought to have. The first iteration of this essay went up in 2003, and there has been a lot of water under a great many bridges since then. Note: I am still not a professional geneticist; but a great deal more is popularly known on the subject than there was back then, and certainly a great deal more is known on the subject now than was when I was originally taught the basics of it, (back when the earth’s crust was still cooling).

Admittedly, exhaustive detail would be neither relevant, nor wanted here, but a discussion online with the LiveJournalist seductivedark in the response column to one of her posts added a number of factors to the equation of which I was not previously aware.

It was already generally known that in our world, in the typical human genome, extra chromosomes are usually a very bad thing. Which is what made me so reluctant to endorse the hypothesis that there were verifiable magical “genes” in the Potterverse. But if the ability to express magic and to conduct magical energies is inheritable (which it unquestionably is) then, if the human genome is still the same 46 chromosomes in the Potterverse, as it is in our world, there has to be something about wizarding genetics that modifies it and makes the additional, magical traits both operable, and, at least arguably beneficial to those individuals who carry them.

Originally, as described above; my reading was that we just couldn’t be altogether certain that the magical qualities of wizards (which still just cannot be explained by any “single gene” theory, from what Rowling had already shown us over the course of the story — nor could magic be a dominant trait) couldn’t necessarily be assumed to be due to genes per se, but that these ‘traits’ were evidently inherited along with the individual’s genes.

Now I’m wondering whether maybe there is indeed something in wizard genetics, or Potterverse genetics, which enables all of those suspected additional genes related to magic to activate without causing the usual havoc that extra genetic material tends to produce in our world.

Because it now turns out that the typical Real World human genome has been discovered to have strings and stretches of apparently “empty” genes in its 46 chromosomes. Blank “genes” which to all appearances do nothing whatsoever, at all, at all.

Perhaps, in the Potterverse, in wizards, those genes are not empty.

• • • •

As seductivedark quoted from one of her anthropology textbooks (with some of her summarization):

“Non-coded nuclear DNA. From Human Antiquity: An Introduction to Physical Anthropology and Archaeology Kenneth L. Feder, Michael Alan Park, 5th edition, 2007, page 331:

“Most nuclear DNA is noncoding, and this noncoding DNA is especially useful because it appears to be selectively neutral. Thus, mutations that accumulate in it are neither selected against, resulting in their disappearance, nor selected for, resulting in an increase in their frequency. Therefore, nuclear DNA may provide a more accurate record of the genetic history of two or more divergent lineages.”

“In addition, the entire mtDNA [mitochondrial] genome is known, that is, all the base pairs have been identified, and there are large noncoding sequences.”

This is about tracing human evolution and presence. There’s a chapter earlier on that discusses current (2007) knowledge. Alleles are variants. They influence a trait but can express it differently. Their example: blood type. We all have blood; we have different blood types.

There are 3.1 million base pairs in the human genome. Possibly 98% of the genome doesn’t code for proteins. Used to be called “junk DNA” but is now known to have some purpose. Some mark the beginning and end of sequences, some regulate function and activity level, some carry DNA to other parts of the chain, which allows things to “reshuffle.”

“Some noncoding DNA is made up of repetitive sequences, some hundreds of thousands of base pairs long, that may do nothing.” (77)

And, “we have learned that the coding sequences are not lined up neatly together but are scattered and interrupted by noncoding sequences. A single coding sequence might code for more than one protein, depending on just which part is transcribed.”

For RNA: “Some classes of RNA may have other functions, such as turning on or off some genes, blocking the action of mRNA [messenger] in producing a protein (which may be important in disease research), shutting down genes and this operating as a defense against harmful DNA or viruses, and even shaping the genome itself by keeping and discarding certain genes.” (77-78)

From what I understand of my Anthro. book, the thingies (note the scientific terminology ;) ) on the DNA strands need to match up to something in order to produce an effect. Eye color to eye color, height to height. I am guessing that the magical genes in a witch or wizard would be matched with blank genes in a true Muggle. Which would, I am still guessing and may be way off, make the magical gene by default dominant. I mean, something plus nothing leaves the identical something, right?”

• • • •

I’m going to have to think about this...

And, yes, “something” plus nothing ought certainly to result in the identical “something”.

Now, I’m sure that at least some of those blank genes may be there to modify the behavior of other genes if those other particular genes (either magical or not) are also present, and do nothing if it isn’t. But a great many of them are probably not. They appear to just be place holders, and their function seems to be to keep those genes that actually do something in correct orientation to one another, on their paired chromosomes, in order to be able to function properly. To make certain that Gene A, on Chromosome A, is six spaces down from Gene B, on Chromosome B. Not five spaces. Or seven. Six. Only six, and nothing but the six. Nor can the scientists examining this phenomenon be expected to figure out what such genes do if they do not do anything that is observable.

But if they are just sitting there empty of any instructions, then you might imagine that they could make fine vehicles for stowaways.

It is also possible that I was on the right track in the first place, and that none of the magical genes activate unless there is a specific one present, or the number of magical genes reaches a certain minimum number to function. But the discovery of there being so many apparently (to Muggle scientists) “blank” genes in most perfectly normal human chromosome strings really makes that explanation sound rather simplistic and unsatisfactory.

Before continuing, I am going to digress into some additional background material: first, I would like to repeat the definition of what I am talking about when I refer to “Magic”.

I base my interpretation of Magic upon the premise that Magic (which is to say, raw, “wild” magic) is a form of energy. It is a non-sentient force, such as electricity, and that in the Potterverse some minerals, plants, species, and individuals within specific species are natural conductors of this energy. And that to be such a conductor is to be “magical”. This premise is explored somewhat more thoroughly in the companion essay ‘A History of Magic’.

I extend this interpretation to include the reading that in the Potterverse most things on either the material or spiritual “planes” are subject to being affected by Magic when these magical energies are properly focused and directed, but that only those natural conductors are able to constrain this energy into a deliberate form, or to direct it to a specific end. This may be done either consciously, or otherwise.

It should also be noted that the effective methods of focusing or directing the force of magical energy in the manner necessary to affect some things on either plane might not yet have been developed, and that, consequently, to affect them may be currently believed to be impossible.

The primary quality that is shared by all magical species, either beast, being or spirit is that they are all psychically “active”. I am going to try to limit my focus to human magic. Human beings, in the main, even in the Potterverse are not, properly speaking, a magical species. I suspect that human magic has developed along somewhat different routes and, upon the whole, over a more recent period than the magic of most other sentient magical species, or “Beings”.

• • • •

A second issue which needs some background is that of the social interactions within the wizarding world as it relates to human magic:

Once again, I will invoke the background material that Ms. Rowling shared with her fans on national television a number of years ago. In these notes it was charted that the population of the British wizarding world, at the end of the 20th century, stood at approximately 25% Muggle-born witches and wizards, 50% halfbloods, and 25% purebloods. In addition, I would like to direct your attention to the statement allegedly made by Arthur Weasley at some point before the series opened, and quoted by his youngest son early in PS/SS that “We would have died out if we hadn’t married Muggles.” I very much doubt that this statement was made available to us by accident.

So. In the first place; we do not know exactly how long it has taken for the population demographics of the wizarding world to reach their current levels. (Although this issue is explored more throughly in the essay: ‘Wizarding Britain by the Numbers’.) Nor do we know for certain how many generations decent from a family founder’s original presumably Muggle-born origins are necessary before the generality of wizarding society stops regarding his descendants as halfbloods. In the case of the diehard pureblood isolationists, all eternity might not be long enough. But the rest of wizarding society is likely to have somewhat laxer standards.

We have also been given no information that would either support nor contradict the question of whether Muggle-born magical children have or have not been steadily assimilated into the wizarding world throughout the entire period that the wizarding world has lived under Seclusion, or if there may have been a period, early in the “experiment” during which this practice had been temporarily interrupted.

The historic background we have been given strongly implies that until the period immediately preceding the formal establishment of wizarding Seclusion late in the 17th century, wizards and Muggles lived side-by-side and interacted with each other as part of the same culture. That, in fact, this had been the case throughout all of human history to that point. Under such a system it would have been far less likely for anyone outside of a certain very narrow social circle to have expended any great degree of soul-searching over whose great-grandparents might or might not have been magical, so long as his or her children were. Or were not, as the case may be.

I have based my own conjectures regarding the social history of the Potterverse upon the premise that with the passing of the International Act of Wizarding Secrecy in 1692, (Or, as stated in later books, 1689) the entire wizarding world formally severed contact with mundane society, and removed itself from it, retiring, as much as possible, behind a “firewall” consisting of Muggle-repelling spells, unplotability, illusions and the prototypes of such portals as those operated manually in the Leaky Cauldron or automatically on Platform 9¾. Or that, at the very least, wizarding families packed up and moved their households to some other district where their magical abilities were unknown, and ceased to allow themselves to be openly identified as wizards.

The only Muggles still to know of this secret, magical “world” at that point were those Muggle husbands, wives, parents, siblings, and offspring who chose to accompany the wizards into their new sanctuaries. All others who could be traced were probably Obliviated before the wizards removed themselves. The Ministries of Magic of the day (more properly the Wizard Counsels, the actual Ministries probably were only formed after Seclusion was adopted) would have also taken steps to limit the opportunities for Muggles to encounter wizards — as wizards — in the future, either by accident or design.

In DHs we get a somewhat confusing hint of this, with the passing mention of a handful of traditional, partially-wizarding communities which wizards had gravitated to for mutual protection and support. In a few of these, such as Godric’s Hollow, where wizards had already been known to occur over several preceding centuries, one really wonders how wizarding secrecy could have possibly been maintained under circumstances wherein the neighboring Muggles were already aware that some of their neighbors had peculiar abilities. Presumably, in such villages Obliviate was used with a lavish hand.

Under such conditions it would have been very difficult for any Muggle-born magical child outside the known wizarding, or partially-wizarding enclaves to have been noted or identified. Ergo; while the articles of the International Act of Wizarding Secrecy would no doubt have allowed for the continued recruitment of Muggle-born magical children into the wizarding world, even after Seclusion was formally established, the actual incidence of such recruitments might have become rather rare. Since, at the time of the establishment of statutory Seclusion, the Muggle population of Great Britain might have produced no more than one Muggle-born magical child in an average year this is hardly to be wondered at.

My premise further postulates that by some point, perhaps about a century after the statutory adoption of Seclusion, it was becoming apparent to those who were in a position to oversee the wizarding world’s welfare, that its population’s birthrate was insufficient to maintain its numbers at a high enough level either to survive over the long term, or, in the shorter term, to retain its current position of dominance in the power balance vis-a-vis the other participating species of the magical Brotherhood.

In addition, due to sweeping social changes in the Muggle world, brought about by the enclosure of the commons and the rise of industrialization, a discernible rise in the number of magical children being born outside the wizarding world was reaching the point that they were becoming a security risk. You can only foster the belief among Muggles that magic does not exist if there are no wizards practicing magic out in mundane view. Unintentionally or not, these children were practicing magic.

I postulate that it was ultimately agreed upon among the wizarding world’s leaders to make a virtue of necessity and to take aggressive steps to identify, train and assimilate these Muggle-born magical children into the wizarding world, both from a security standpoint by removing them from the general view of Muggles, as well as to lay a claim upon these children’s talents to offset natural attrition in the wizarding population, and to increase the magical work force.

It would have been at this point that a cross-section of the secluded population, who had nothing but bad associations with Muggles — dating from the era that Seclusion had been determined to be necessary for wizards’ continued survival — would have begun to put a renewed emphasis upon the need to distinguish those who were descended from sound, old, pureblooded wizarding ancestry, from anyone who was an interloping mudblood. I postulate that this particular point in time was most likely to have been early in the first half of the 19th century. The wizarding world has been dealing with the ramifications of this situation and the response to it ever since. With varying degrees of success.

A reasonable argument can be made that this inclusive policy may have been adopted anything up to a century later, but this view is difficult to reconcile with the current population demographics. It takes time for an annual intake of 2-10 people to become established as a quarter of the whole population.

And, for that matter, since I did not see the broadcast in which the information regarding the population demographics was given, I am working from hearsay. Consequently, I am unsure whether Rowling’s statements were that Muggle-born witches and wizards were a quarter of the wizarding world’s population, or only that they made up a quarter of the student body of Hogwarts. The difference is slight, but there is a difference.

All of which pitches any exploration on the inheritance of magical conductivity into an argument of semantics.

For one thing: I believe that while the terms halfblood and pureblood were probably in use long before the establishment of Seclusion, I doubt that the term “Muggle-born” is of any such long-established coinage. That term has, to my ear, the ring of the same sort of Victorian euphemism that rechristened the “breast” of a fowl as the “white meat”. Regrettably, I suspect that the original, pre-Seclusion term was probably our old un-friend, “mudblood”. A term, which, while certainly no compliment, at that point, may not yet have acquired many of the pejorative implications that it carries today. In a coarser age, it was probably no more negative a term than that of “native”. Although, admittedly, it had probably also been no less so.

On the other hand, I also have a strong suspicion that in that more distant period the term “mudblood” might not only have been every bit as pejorative, but it may have carried a very different implication altogether. Given the probable odds in such matters, traditionally such children were a good deal less likely to be the unanticipated magical offspring of two blameless apparently Muggle parents than they were to be unacknowledged halfbloods whose true paternity was unknown; raising serious questions and issues of consanguinity once the child had been absorbed back into the magical community. To designate a child a mudblood may well have been just another way of calling it a bastard. Or, as such children were referred to by Muggles, “base-born”.

The real objection in such cases may not have been to the open matter of the child’s apparently Muggle birth, but to that of its shrouded magical ancestry. The application of the slur to today’s legitimately “Muggle-born” magical children is due to these later-day magical children’s unknown magical ancestry being presumed untraceable.

For that matter, the term “halfblood” seems to have also undergone a shift in meaning since the establishment of Seclusion. Whereas, at the time the seclusion of the wizarding world was imposed, the term may well have been applied primarily to those persons who actually were the children of a mixed marriage (or some other, more irregular connection where paternity was acknowledged), we have already seen that this term is far more broadly applied in modern day. The presumed need to maintain a distinction between purebloods and everyone else has resulted in the designation of halfblood now being applied to children with as little as one Muggle-born magical parent, grandparent or, quite probably, great-grandparent or beyond. Even though all of the child’s recent antecedents are all, in fact, magical.

It is unclear in canon as to just how many generations of functioning magic are necessary to cancel out the “taint” of Muggledom in the eyes of general wizarding society — which is not the same standard as that of the most rigid of sticklers, such as those which are still upheld by blood-purity fanatics on the order of the late Madam Black.

It is also uncertain what the percentage is of such technical halfbloods as opposed to literal halfbloods that goes towards making up that 50% of the current wizarding world’s population which was referenced in Rowling’s statement. My own suspicion is that it accounts for most of them; since the continuing practice of at least statutory Seclusion considerably limits the opportunities for such attachments which result in literal halfbloods.

Which reminds us: we know of no instance in canon wherein a witch or wizard married, or became otherwise involved with a Muggle in which the Muggle was informed of their partner’s magical status ahead of time. This practice seems not, in general, to have contributed to long-lasting mixed marriages with multiple children.

(Note: we do not have full information regarding the Creevys. Their father is a milkman, and presumably a Muggle, but since Professor McGonagall is heard to be chivvying a Creevy out of the castle (Dennis) during the evacuation of the lower years, before the final confrontation, and since we know that Muggle-borns had been presumed to have been banned from Hogwarts that year, I think we must re-categorize them as literal halfbloods.)

But, returning to the question of the inheritance of Magic:

Keeping all of these distinctions in the back of our minds, we will first deal with the unambiguous and the inarguable; the statement made that 25% of the current wizarding world (or at least 25% of a Hogwarts year’s average enrollment) is Muggle-born.

The magical conductivity of Muggle-born wizards has to come from somewhere. Rowling stated on her website in 2004 that magic is a “dominant and resilient gene”. The problem with Dominant genes, however, is that they are not resilient. Once a Dominant gene fails to be passed on, it’s gone. It does not skip generations. It is either there, and active, or it is completely out of the equation. Unless Ms Rowling defines magical conductivity as a spontaneous mutation which occurs regularly in about 0.005% of the mundane births within the Hogwarts Quill’s sensory range, Muggle-born wizards cannot be the result of a Dominant gene that is not present in their parents’ DNA.

Admittedly, I am not a geneticist; and so I cannot tell you whether there is any mutation which occurs in a consistent and recognizable form at this level of regularity, and moreover, one that breeds true, to serve as an appropriate parallel. There may be one, possibly more than one. But I find it difficult, even impossible, to suspend my disbelief far enough to accept that the “exact same” recognizable mutation can spontaneously occur at such a rate that one quarter of the wizarding population carries it, in even such a complete AU as the Potterverse. If this is the case, Petunia Dursley is right. They are freaks.

Nor does the human race naturally select to magical conductivity. Humans are not an inherently magical species. Magical conductivity is an aberration in humans.

Rowling’s more recent statement, that Muggle-borns do have wizards in their ancestry, would support the reading that Magical conductivity is, indeed, a Recessive trait. This is a lot easier to believe.

However, neither can any “single gene” theory adequately explain the broad range of various levels of magical ability displayed throughout the Potterverse, or the existence of those “rare” gifts which have been noted in the story to date. One size quite clearly does not fit all.

And given that wizards, in canon, are also cross-fertile with other magical species, *as well as* with non-magical humans, how is one supposed to account for the inheritance of non-human magical abilities (which has also been demonstrated in canon) within a “single Dominant gene” model of magical inheritance?

You can’t. I’m not even going to try.

• • • •

Of course, not everyone agrees with me. And there is no guarantee that I am right. Potter fans have been postulating different theories on magical inheritance for over 20 years now.

Besides, much of the context in which Ms Rowling’s statements were made make it clear that what she was responding to were questions of whether some people were magical but not magical enough to attend Hogwarts. (Stan Shunpike of the Knight bus having been the specific case given.)

That is a different issue altogether. Ms Rowling’s response that one is either magical or one is not, is a statement with which I readily concur. One can either conduct magical energy, or one cannot. This statement prompts absolutely no argument from me. But her original explanation of why one can either conduct magical energy or not simply does not hold water. It is over-simplified, over emphatic, and not only contradicts established scientific findings, it contradicts what she had already shown us in the text. What she has cumulatively shown us simply *does not work that way*.

And whining that; “but it’s magic” is a cop-out. Even Magic needs to follow observable rules.

• • • •

That such a high percentage of the wizards currently alive in Great Britain today were each born from two apparently Muggle parents (and that fully 2/3 of the rest are still tracing their decent from Muggle-born predecessors) would — first — tend to suggest that the population of the wizarding world, when the decision to aggressively seek out and assimilate Muggle-born children was made, must have been in dire straits.

It also would tend to indicate that, in the Potterverse, there is already a fairly high predisposition towards Magic lurking in the mundane gene pool of Great Britain. That every wizard and witch that we have met does not appear to have the same capabilities for Magic would also tend to suggest that the inheritance of Magic is not dependent upon any single gene which is either present or not, but upon some more complex system entailing a combination of influences. Although other theorists do have other interpretations of that, of course.

In addition; that certain specific magical gifts have been stated outright in canon to be rare, even among wizards, would tend to suggest that there is a whole range of magical traits whose total effect may be cumulative.

Taking all of these factors into account, it is easy to form at least a tentative hypothesis that most, if not all of the traits required for conducting magic are passed down, not as Dominants, but as Recessives. As highly resilient Recessives, and that they can be passed along as Recessives through several, untraceable generations of apparently normal Muggles until they are given the proper conditions to activate, producing a Muggle-born wizard. We have already learned in our own mundane science that once a Recessive has been introduced into the genome, either from a different genetic strain than that of the local breeding population, or through mutation, it can stick around for aeons.

And that may indeed be our answer. One thing that appears to be unquestionable is that whatever the “minimum requirement” of magical traits in a child’s genetic inheritance may need to be in order for the child to register as magical, it appears to be fairly low. Otherwise you would not have generations of untraceable recessives suddenly throwing out a wizard without shedding some if not most of the additional magical recessives over time in the process. So, while magical inheritance itself cannot be due to any single gene, it may require only one of a specific range of magical genes to activate. And that while it may take only one magical trait to activate magical conductivity itself, that conductivity may be further enhanced by any number of potential additional magical traits which may or may not accompany it. Or possibly, there is some other factor involved. I will be returning to this possibility presently.

As to the original source of some of those rare, highly specialized magical traits which are floating about in the human genome of the Potterverse; an unpalatable, but unavoidable possibility is offered by the fact that canon has already shown us that human wizards are only one of a broad spectrum of sentient magical species. And that human wizards have been demonstrated to be cross-fertile with more than one of these other magical species — as well as with normal, non-magical humans. What is more, we have been shown that some of the descendants of these wizard/non-human-magical crosses are observed to possess magical traits specific to their non-human ancestors. It has not been either suggested nor confirmed whether the same sort of cross-species fertility applies to Potterverse Muggles.

Given that Muggles are typically not psychically active enough to even be able to see magical entities such as those that reside on the spirit plane, Dementors for example, or, even more commonly, ghosts, the question as to whether a Muggle might be capable of producing offspring, let alone fertile offspring, through cross-breeding with a partner from a non-human magical species native to the merely physical plane sounds unlikely. No more than they could produce fertile offspring with orangutans.

Although… given that allegedly, a human being can share up to 25% of his genetic material with a banana, I admit that I could certainly be wrong about that.

In the light of that, what seems quite probable is that the bulk of the folktales regarding young men and women who captured selkie or veela wives or who married husbands from “under the Hill”, in the Potterverse may relate the stories of unacknowledged wizards and witches in the pre-Seclusion period when wizards lived out among Muggles. Back when all magic was Dark (i.e., chaotic) magic, and they voluntarily limited their use of magic in order to forestall any sort of progressive dementia that might result from overexposure to chaotic influences.

Or, conversely, it is not impossible that such pairings are the origin of human magic altogether. In the days of prehistory, when humans were less numerous, such “others” may well have been more inclined to undertake such short-term liaisons with them.

The children of such crosses were sufficiently human in appearance and genetic make up that they were able to find mates and produce offspring within the local community of Muggles and their non-human parents’ highly specific, non-human magical traits were introduced into the mundane human genome at that point*.

*This is itself a simplification of terminology. As stated above, it is uncertain whether the magical traits of non-human magical species can be physically incorporated into human chromosomes. What seemed more likely, at the time I drafted out this hypothesis, was that these traits attach themselves to the DNA by some other, perhaps undetectable method. But more recent understanding of genetic structure offers a good deal of leeway in such interpretations.

Given that it appears to only be human magicals who are damaged by the conduction of chaotic magic over a long period of time, it is possible that the results of such crosses have some degree of resistance to such.

It should be noted that from an evolutionary standpoint, these highly specialized traits, indeed, all magical traits, appear to be very late introductions to the genetic legacy of human wizards. Indeed, these were introduced well after humans had become humans. It is chiefly in consideration of the fact that such non-human traits have unquestionably been introduced in human wizards in the Potterverse that I offered my suggestion that the inheritance of magical traits may be dependent upon some element other than by merely physical genes. I have not chosen to deeply explore the possibility that specifically human magic may not, in fact, exist, and that all magic in humans descends from an introduction of magic from unspecified non-human origins at some point in prehistory.

What did seem to be a very strong possibility is that the presence of these more recently introduced non-human magical traits increases the chance that any tendency toward an underlying magical conductivity will be activated. So that while it is certainly possible for such conductivity to exist without additional acknowledged non-human traits, as such traits become more widespread in the gene pool, the lower the concentration of raw magical conductivity will be necessary to produce a child who will be psychically active enough to register as Magical. Or, put another way, such introduced traits add to one’s total, and they all count toward collecting the minimum requirements necessary to produce a functioning wizard. And, as such traits become both more widely dispersed, and more highly concentrated in a given local gene pool, the predisposition for that community to produce magical offspring rises.

The so-called Dominance of the magical genes to which Ms Rowling refers, is probably meant to indicate that the percentage of literally halfblood wizards actually born is significantly higher than the anticipated 50% that basic genetic theory in a single gene model would suggest. Even dismissing three-quarters to five-sixths of the halfbloods of Rowling’s world as being more probably technical halfbloods than literal ones, the actual number of such mixed pairings remains far below what was probably the norm prior to the establishment of wizarding Seclusion.

Clearly either these literally halfblooded magical children are receiving some magical traits from their non-magical parent, or the magical traits, although they remain in the gene pool in the manner of Recessives, do not function in exactly the same manner as true Recessives in that there is no associated Dominant trait which overrides them. In fact, quite a few magical traits, unlike a typical, non sex-linked recessive gene, may activate even when that specific trait is not inherited from both parents. It may only require that the genetic contribution from the other parent give neutral instructions rather than presenting an outright conflict. In the case of there being no actual conflicting trait, as is almost certainly the case with traits introduced from non-human origins, the trait, once it is present, activates independently. Once the basic minimum requirements are met, any child possessing enough of these traits will be able to conduct magic.

Probably. But we still seem to be overlooking something that could be important.

Which brings us to a closer examination of the final category in the Muggle-to-magical continuum. I am referring, of course, to Squibs. Squibs are identified in canon as the non-magical offspring of magical parents. I am not sure that this is the best way of describing what is going on, here.

It is at least somewhat evident to the reader that Squibs cannot be absolutely interchangeable with Muggles.

If the Potterverse is truly parallel to our own world, then the average Muggle can be expected to be completely unaware of the presence of ghosts. They should certainly be incapable of seeing or interacting with other varieties of spirits which are not ghosts, such as, for example, poltergeists. Or Dementors.

Argus Filch, the caretaker of Hogwarts, has been identified as a Squib. But, whereas the typical Muggle would probably be unaware of any entity native to the spirit plane, Filch has no difficulty seeing and communicating with the Hogwarts ghosts. He also clearly has an ongoing two-way relationship with the Castle poltergeist, Peeves. He can also obviously see the castle. Which we are told flat-out, Muggles can’t.

However; Ms Rowling also states on her website that Arabella Figg lied when she claimed that Squibs can see Dementors. Given what Rowling had already established regarding the psychic abilities of Squibs in canon, in the case of Mr Filch, this initially seems to be a bit of poor judgment on Ms Rowling’s part. But in fact it may well be an indication that one size does not fit all Squibs any more than it fits all wizards. Mr Filch is, demonstrably psychically active to at least some degree, regardless of whether Mrs Figg shares this quality. But no Squib, however perceptive, is able to actually conduct magical energies. Still, in her website update of December 10, 2004, Rowling does imply that Squibs are able to activate and control previously charmed implements. (If they are not, then Filch is confiscating items that he cannot control or deactivate.)

We don’t know for certain whether Muggles can control charmed implements as well, and there are some indications that they can’t. Arthur Weasley’s old Department would have a lot less work if they could. Rowling hints that a Muggle getting hold of a wand would be an accident waiting to happen. But Rowling digs herself into a deeper hole every time she answers a question on this subject, so it is probably just as well to stop asking her.

Frankly, we come up with more consistent explanations ourselves.

Rowling has also given us the statement in canon that Squibs are very rare. We have only heard of three Squibs in canon. Argus Filch, Arabella Figg, and a connection of the Prewett family who went off to make his fortune among the Muggles. Rowling also claims that one of the names blasted off the Black family tapestry was in fact a Squib. But this information is at least technically off-canon.

However, the evidence is now mounting up that just because wizards in the Potterverse consider Squibs to be rare, the actual likelihood of this actually being the case is receding ever more firmly into the distance. In fact, the whole question of Squibs is now looking not so much like yet another can of worms to have to sort, but as the unacknowledged elephant in the room.

Particularly since no one in the Potterverse, neither wizard nor Muggle, has any way of determining just how widespread Squibs may actually be. No one, after all, knows any simple way to be able to distinguish a Squib from a Muggle.

Or, in other words, it isn’t Squibs that are rare.

It is wizards that are rare.

And that it is wizard-born Squibs that are the rarest of all.

My own earliest theories regarding a social history of Wizards and Muggles are now slightly hampered by Rowling’s various DHs monkey wrenches. Because, post-DHs it appears that at least half of the 18th century Muggle-born would have probably been identified and trained, since those particular individuals were most likely to occur in places like Tinworth and Upper Flagley, where there was already a traditionally high concentration of magical traits in the local population. And, more to the point, there were still wizards living there who could identify them.

But as to the origins of magic in the human population itself, I do not see any reason to jettison my original extrapolations. In fact, we may need to expand it. It has become very easy now to postulate that all magic in humans was originally non-human in origin.

Or, in other words; they were humans before they were wizards.

Yes, wizards developed that recently, evolutionarily speaking.

And if they developed from non-human genetic material being introduced to the human genome, then it’s small wonder if there are some problems that come along with it.

I really do think we need to do no more than to examine the local folklore. Just about every culture there is seems to have generated stories about various uncanny “others” who look human, but who really aren’t. And, in just about all of such cultures, there are all sorts of stories about young humans who have been deceived by (or who have entrapped) these others, married them, generally had kids by them, and then at the first opportunity the alien husband or wife has disappeared, leaving the kids behind.

In the Potterverse there still are non-human “others” walking around by daylight (or moonlight) who various wizards and witches have married and produced children with. Rowling endorses such cross-species interbreeding in the course of her story, demonstrating not only that such crosses produce offspring, but that they produce fertile offspring, and that the children of the offspring also are able to express out-of-the-ordinary magical abilities peculiar to their non-human ancestors.

There is no way that can happen under “a single magical gene” system. Plus right off the top we also get those “rare” wizarding talents like the seer’s gift, or the ability to express and understand Parseltongue (heaven only knows where those came from). So it would hardly be unreasonable to start speculating that in the Potterverse nature so abhors a vacuum, that it has found something to put into the slots of those empty, non-coding genes...

And, so long as we are looking at folklore, as I point out in various other essays in the collection, in the folklore of the British isles, wizards were never really all that uncommon. Most tribes, or clans had at least one, and others could generally be found across the countryside.

My original speculations questioned whether a “true” Muggle would also be able to interbreed with these non-human magical creatures. But if there are “empty” spots on the underlying chromosomes, then there are ready-made placeholders for any additional magical genes just sitting there, vacant, waiting for them to slot themselves in, and no way to identify them, or their carriers, unless the carriers are able to actively express magic.

Which, in a direct wizard/Muggle cross they usually do.

• • • •

In any case; I have long proposed that any Muggle in the Potterverse who has ever really seen a ghost, is probably what amounts to a Squib. The same may be said for any authentic “psychic” or spiritualist medium — assuming there are any in the Potterverse who are not actually wizards.

In fact, any Muggle who has ever been involved in a genuine encounter with paranormal phenomena, such as, but not limited to, prophetic dreams or seeing visions was probably actually an undocumented Squib.

If we superimpose some of the unexplained psychic phenomena from our own world onto the Potterverse one might also level a degree of suspicion toward at least some of the everyday miracles attributed to their recipient’s faith. I would also add to this list any Muggle who has ever experienced the sort of unexplained burst of strength or speed usually attributed to adrenaline under circumstances of extreme stress. And while we are at it, let us say that most of the people who have experienced those miraculous spontaneous remissions to various medical conditions might also bear some closer examination. As might their physicians or caretakers.

Given that the ability to wandlessly cast a glamour is one of the very commonest magical traits shared by many, if not most, of the non-human magical species whose abilities have been added to the wizarding “genome” of the Potterverse, one might also want to consider the case of various classes of celebrities, with particular attention to those who seem to have managed to become famous despite the fact that they have accomplished nothing in particular, whatsoever (i.e., all those celebrities who are unaccountably “famous for being famous”) as likely candidates to be the sort of people who, in the Potterverse, would most probably turn out to be Squibs.

Nor is it too much to consider that some cases of what have been diagnosed as mental illness, or some forms of neurological abnormalities may in fact be the result of an impaired ability to conduct Magic. (Ariana Dumbledore, I am looking at you.)

If one wishes to speculate on the likelihood of Squibs around us there is certainly no shortage of possibilities. But none of these are relevant to the big picture. Muggle carriers of magical traits for the most part are indistinguishable from Muggles with no magical component to their genome whatsoever.

The stated rarity of documented Squibs is quite likely to be something that we can take Rowling’s word on — with the prescribed grain of salt. With the magical genotype being as resilient as it appears (and that much Rowling has shown us in canon) it would take a considerable screw-up in inheritance for a child of magical parents not to be magical as well.

While we’re at it, it is also almost certain that “Squib”, like “Muggle-born” is another comparatively recent term in the wizarding world. One that has only been adopted since Seclusion was actually established. When one considers that prior to the formal and “complete” separation of the two worlds, if wizards and Muggles lived in the same communities and frequently intermarried, the non-magical offspring even of two wizarding parents might well have simply been regarded as Muggles, who their parents’ magic had skipped. It was only after seclusion and such children still managed to occur that a specific term was applied to them.

Having now gone out on an unconfirmed limb, however, I suggest that there may be a specific reason for the birth of a Squib. For this, we have a variety of possibilities.

It is possible that the magical traits that a Squib inherited from one or other parent have been somehow disabled; possibly due to parental exposure to some form of magical accident, or some particularly damaging form of curse. Or, conversely, that a Squib’s natural channeling of magical energies is designed to diffuse the flow of such energies in the same manner that I have proposed some juvenile wizards have unconsciously taught themselves to do in order to eliminate any accidental magical “breakthroughs”, leaving them with an insufficient magical reservoir to express a spell.

The simplest explanation of course is that, somehow, one or other of the traits necessary for full magical conductivity simply was not passed on, although both of a Squib’s parents possessed it, or that both parents were very low-powered magicals who somehow did not pass on to him the sufficient minimum number of magical traits to produce magical conductivity. But I’ve come to suspect that that explanation may be a little too simple. It doesn’t really fit what we have been shown.

A more interesting explanation that I can think of is that in Squibs, we may have the equivalent of those rare brown-eyed children of blue-eyed parents. Let me restate: human beings are not a magical species. To all appearances, these non-magical children’s genomes have somehow re-set themselves to the underlying human template of non-conductivity, overriding the instructions of the established Recessives for conducting magic.

Except that under normal circumstances, there is no countering factor to override such Recessives. If they are present, they activate.

But now suddenly they don’t. Something is now preventing it.

Apparently, something has been added to that child’s genome. Something which suppresses magical conductivity.

But, if it works the same way as it does with the eye color, the Recessives are still there. If it was just the fact that something went wrong in a single case, a Squib, even when paired with an apparent Muggle would be more likely than not to produce magical offspring, even as those rare brown-eyed children of blue-eyed parents have typically been known to produce blue-eyed offspring themselves. (And indeed, Mafalda Prewett, the Weasley cousin who didn’t make it into the final version of GoF was intended to be the witch daughter of the Prewett family’s Squib cousin and his Muggle wife.)

Which suggests that the common definition of a Squib may be in need of some slight modification.

In cases where only one parent is magical, any non-magical child will typically be perceived to have taken after the non-magical parent. In a case where neither parent is magical, the child will be assumed to be a normal Muggle.

Given the number of magical traits that are floating about in the Potterverse, however, this may be far from the truth. In fact, I would postulate that, if Squibs are redefined as; “non-magical persons carrying magical traits”, Squibs are, in fact, very far from being rare. It is only wizard-born Squibs that are rare. That, indeed, there is a significant number of what amount to undocumented Muggle-born Squibs roaming about the Potterverse, and that they outnumber Muggle-born wizards by several hundred percent. In fact they probably outnumber wizards of any sort of ancestry by a couple of hundred percent.

And, to be strictly accurate, these individuals are absolutely NOT magical, since under virtually all normal circumstances they are just as completely incapable of conducting magical energies as is any true Muggle. But, since no one seems to have ever considered that they are out there, no one has ever attempted to identify them. They are, consequently, completely undocumented.

But they are highly significant.

For example;

If this is the case, I would say that every Muggle-born magical child is, without exception, the result of a pairing that involves at least one of these Muggle-born Squibs, and that if such a pairing can produce one magical child, the odds of its producing others are automatically that much higher.

I suppose that — rarely — in the case of two wizards with narrow-ranged gene sets, if something goes wrong, they might indeed manage to produce a classic example of what we spent years believing was a wizard-born Squib. All indications suggest that while there may be no effective maximum number of magical traits necessary to produce a fully magical child, there does certainly seem to be a minimum. In the case of both parents possessing only the barest minimum number of traits necessary to conduct magic themselves, very little needs to go wrong in order to miss this particular boat. We used to think this was the case. The wonder is that it does not happen more often. But it doesn’t. And maybe it can’t.

But as to the stated “rarity” of Squibs. I originally supposed that Squibs occur among wizards at about the same frequency that Muggle-born wizards occur among Muggles. That it is the only difference in the population numbers of these two groups which accounts for the extreme apparent rarity of Squibs. Whereas the Muggle population was large enough to produce between 10 and 15 Muggle-born witches and wizards in any given year, it takes the wizarding world some 15-20 years or more before generating a comparable number of births among which one might expect to produce a single Squib.

Well, with Rowling’s statement in July of 2006, that the magical human population of Great Britain and Ireland numbers around 3,000 (and more realistically it would be somewhere between 3,500/4,500 up to about 10,000) the incidence of 1 Muggle-born magical child to some 80,500 non-magical births seems unlikely to be matched within the wizarding population of 1 Squib to anything like that number of wizards, or Squibs would be even rarer than they are already. But the likelihood of 1 Squib in 15-20 years still seems within the range of plausibility.

And, as stated above, the magical equivalent of chromosomal damage as a result of curse injury or exposure to some dangerous magical process or material might be another contributing factor for the birth of a Squib.

And it could possibly explain other related problems that wizards might have with their magic. Such a possibility might account for why some people in canon with a normal to high amount of magical conductivity might still show a pronounced weakness in one or another area.

However, I no longer am so willing to adopt any of these as the most likely explanation for the existence of Squibs. I am now of the belief that Squibs are not produced by a lack of inherent magic, but that they are due to the addition to something else.

Namely, a “single gene” theory of a gene that suppresses magic.

If wizards are still, evolutionarily, a recent hybrid, one which may have inherent problems with its magic, it wouldn’t be astonishing to speculate whether or not the underlying genome may not have attempted to develop a defense against it.

Or in other words; they were wizards before they were Squibs.

Squibs are an even more recent evolutionary development.

A highly successful one, too, from a strictly biological standpoint.

Part of this next is probably based on intellectually flabby thinking. But in the manner of most theorists who have drafted out something that already *almost* works in just about every condition, if you throw them a new condition they can’t help but examine whether the already-built theory can contain it. The possibility that Squibs are an evolutionarily recent development needs to be examined against whether such a possibility has any place within the existing paradigm.

And it does. Boy howdy, does it ever.

Because I had already extrapolated that magical conductivity, improperly controlled, could result in fatal incidents, wherein an individual whose magical conductivity had matured, but who was working without proper controls, safeguards, or focusing assistance, might manage to (intentionally or not) invoke a magical charge too great for him to survive.

I am now beginning to wonder whether, perhaps, whatever the factor is that causes Squibs is a factor which is attempting to “protect” the basic underlying human genome from the result of all of those foreign genes (many, very possibly all, of them originally from non-human ancestors), by disabling the full expression of magic, but doesn’t actually get rid of any of the additional, magical traits.

If this is the case, then if my underlying postulation that Magic really is a potentially dangerous form of energy, on the order of static electricity — which in high enough voltages can kill (lightning, after all, is static) — particularly if such episodes are triggered by emotional stress, then for a magical hybrid sub-species of a species which was never designed to conduct such energies, to develop a biological factor which is expressly designed to suppress the conduction of such energies makes evolutionary sense. Squibs are effectively (and efficiently) “grounded” against conducting wild magic. Clearly there would be a considerable advantage in survival rates for a population which harbors the genes which would make the conduction of these energies inevitable, to inherit that one as well.

And the ones who survived usually had.

• • • •

From the population numbers which we have been given, however, (it is always dangerous to take Rowling at her word on any issue that depends upon numbers), clearly, the majority of the human population of the Potterverse carries neither any discernible magical traits nor the Squib factor which suppresses them. These are the “true” Muggles who carry no magical traits at all. And they comprise, by far, the majority of the human species of that world.

Now, back in 2003; at the point that I hammered out my original theory, I wasn’t reasoning from the postulation that there was a legitimate “Squib” gene. I did eventually include a fairly lengthy digression from a LiveJournalist named Jehnt, who had laid out such a theory, but I didn’t ascribe to it myself, since it seemed to me that if there really was such a thing, Squibs would be far more common than they are.

But now I’m beginning to suspect that by taking Rowling at her word, we may all have been in the habit of looking at the whole issue back-to-front.

As stated above; it isn’t that Squibs are rare. It is that wizards are rare.

Squibs are merely uncommon. And most of them are all right out there passing as Muggles. And neither they nor the Muggles have any awareness of the difference.

And the Squib factor is Dominant.

Consequently, the minute a Squib descendant shows up who doesn’t inherit the “Squib” factor, boom. You’ve got a wizard. And it also naturally follows that the Squib factor would be vanishingly rare in a self-isolated community entirely composed of wizards — who do not have it.

And, until wizards separated themselves out, which has only been in the last few hundred years (not even a blink of the eye in an evolutionary reckoning) there was hardly any way of being able to distinguish a Squib from a Muggle, since most families were perfectly aware that they were of mixed blood already.

And, given the resilience of Recessive traits, there will always be wizards. And there will always be new ones whenever the Dominant Squib factor fails to get passed on.

And it will fail. Because it is a Dominant trait. They all eventually fail.

But, because it is a Dominant trait, one that carries a genuine survival advantage to it, there will always be a lot more Squibs than wizards.

My original hypothesis, which still seems fairly sound, was that wizard-born Squibs were rare in the same way that brown-eyed children of blue-eyed parents are rare. It looks like that they may be rare in exactly the same way such brown-eyed children are rare.

With the difference that they are rather more likely to pass the condition on.

Such brown-eyed children are completely impossible from the standpoint of rudimentary genetic theory. But it obviously happens, and such kids are definitely the offspring of those particular parents. There is no need to go looking for the milkman. It’s as if the genetic material has spontaneously “reset” itself to the standard human default of brown eyes, despite the fact that there was no brown-eyed gene available to be passed down from either of the child’s parents. But the recessive blue-eyed gene is still there, even if it doesn’t express itself in that particular child. Such kids frequently produce blue-eyed offspring themselves.

But if the Squib mutation (if it is a mutation) is there specifically to suppress magic, and is reasonably widespread in the general, rather than the magical population, then with all the magical traits that are floating around in the gene pool, it’s really not all that astonishing that a full quarter of an average Hogwarts year’s intake is made up of kids from families in which there is no known history of magic. These are the descendants of Squibs, in whom the Squib factor to suppress magic has not been passed on.

And since witches and wizards tend to produce only witches and wizards, we can conclude that the Squib factor is a Dominant trait, and that it is at least somewhat pervasive throughout the human population. It is impossible to tell at a glance how widespread magical traits are in the Potterverse since, in most cases, the Squib factor is suppressing them.

And like any other Dominant trait, once it fails, it’s gone.

Or, it’s gone until it spontaneously resets itself. And that may take generations. And the following generations after that may still produce wizards if they manage to shed it again.

In an isolated wizarding society which has self-secluded itself specifically on the basis of not carrying the Squib factor, Squibs would be understandably rare. In these individuals the factor has sprung up spontaneously. Neither of the child’s parents had it in order to pass it on.

• • • •

I now wonder whether the frequency of occurrence is anything like albinism? Albinos are certainly rare, in just about any species, but they do occur, and in non-human species the trait is sometimes deliberately bred for.

But, as seductivedark pointed out, when a sport mutation occurs in a species, there is typically a reason for it to perpetuate. It must be generally beneficial, or at least not actively harmful to the species, or the species would either shed it, or it would die out. Suppressing the conduction of magical energies is clearly a beneficial result. But there may be additional side advantages as well.

Rowling, after all, assures us that there are any number of specifically magical diseases which are what carry most wizards off, since they do not die of old age. (Note: *le sigh* neither do we Muggles, really. We all die of identifiable causes, and “old age” is not one of them. One really wishes that Rowling would think these things through before she tosses them at us. Or at least consider that she is not, in fact, only talking to 9-year-olds.) The Squib factor would almost certainly produce an immunity to any magical malady, since it seems to suppress any expression of magic by the individual.

As to any other speculative benefits of suppressed magic, my original hypothesis was that Squibs can see various magical phenomena while Muggles can’t, and are able to control already-charmed objects. This is unquestionably true within canon. My observations regarding Filch and the castle (and the ghosts), above, also still stands.

But Rowling also tells us that wizards do not get cancer or various other Muggle health conditions. So it appears that unless this is merely the result of sophisticated medi-magic, it seems to be Rowling’s intention that having magic, or perhaps only magical traits, can suppress, or produce resistance to various Muggle diseases.

So it may go both ways. It is possible that even suppressed magic can convey a resistance to certain Muggle diseases. It might be interesting to learn if either active magic, or the Squib factor, or both, convey a resistance to various auto-immune diseases like Rheumatoid Arthritis, Lupus, MS, or the rest of that catalog. Although it would appear that neither the Squib factor, nor active magic give anyone any immunity to most common human epidemic diseases (or head colds).

But if such should turn out to be the case, I would imagine that in the Muggle Potterverse, most of the Centenarians (of which I am sure they have as every bit many as we do) would, to an overwhelming degree, turn out to be undocumented Squibs.

• • • •

Which introduces another possible wrinkle.

The ww has separated out into a whole community without the Squib factor, but there is no clear and easy way to tell a Squib from a Muggle.

And it doesn’t work so smoothly if the Squib factor is Dominant, and reasonably pervasive in the general human population. Which it seems to be.

Wizards within the ww almost universally produce wizards. And if the Squib factor manifests spontaneously, the resulting Squib can still produce wizard offspring, even with a Muggle partner. Perhaps especially with a Muggle partner. Mafalda Prewett (the never-introduced Weasley cousin) was supposed to have been the daughter of Molly’s Squib cousin and his Muggle wife.

Ergo; the Squib offspring of wizarding parents will still carry the potential of not inheriting the Squib factor, and once a Dominant trait fails to be passed on, it’s gone. Mafalda is a witch. If she stays in the ww, her children will most probably all be witches and wizards. She does not carry the Squib factor to pass down to them. The only way for her to produce Squibs would be for the Squib factor to occur spontaneously in her descendants. It does not skip generations.

It would appear then, that Mafalda’s mother is most likely to have been have been a true Muggle, with no Squib factor to pass on from her side rather than another undocumented Squib. Statistically, one would expect a 50/50 chance of producing wizards in a Squib/true Muggle cross. But by this time there isn’t any way to identify “true”, Muggles.

The same 50/50 chances stand for producing a wizard if a known Squib’s partner is magical. That is not the kind of odds that most magical families are eager to try to beat. Taken with the apocryphal information that the Black family blasted their only known Squib offspring from the family tapestry, this strongly suggests that most Squibs are encouraged to leave the wizarding world and to seek their fortunes out among the Muggles.

Consequently, if an acknowledged Squib leaves the wizarding world, and pairs up with an undocumented Squib, most of their children will probably not carry any possibility to not pass down the Squib factor. Only one in four of their children has any chance of being magical, and there might be a reduced chance of active magic turning up in a grandchild. And then only if their child’s partner is either a true Muggle, or magical themselves.

Of course, Mrs Prewett may also have been a Muggle-born Squib with hidden pseudo-recessives for magic. The (titularly Muggle) Prewetts might still produce both magical and non-magical children, but the statistical probability for magical children in that case drops to 25%.

Unlike with the trait for Sickle Cell Anemia, which, when inherited from only one parent conveys a resistance to malaria (and from both produces the condition of Sickle Cell Anemia, which is a very unfortunate thing), we know of no disadvantage pertaining to inheriting the Squib factor from both parents apart from the inability to express magic. The result, in that case would appear to be merely to make the factor rather more widespread in the apparently Muggle population since such carriers have no alternative but to pass it on.

Since true Muggles do not carry this factor, eventually among Muggles it will be lost when it fails to be transmitted, but in the meantime it may perpetuate itself over several generations. Regardless of whether or not those generations have also inherited the original Squib’s potential for active magic. By the time the Squib factor fails to be passed on the magical capability may also be gone, although it is very difficult to say as much with any certainty when you are talking about Recessives. Recessives have real staying power.

Another element contributing to the rise in the number of magical children being born outside the wizarding world is the underlying truism that a rising tide lifts all boats. It is only to be expected that as the overall number of births in the general population rises, more magical children will also be born, even if the rise in their numbers is statistically insignificant when compared against the total number of mundane births.

According to Strauss & Howe, whose theories regarding the rhythms of cyclical human social history would certainly apply to the ins and outs of mundane history in the Potterverse, cyclical history is punctuated by “great events”, which, once resolved, tend to lead into periods of relative peace, prosperity, and population explosions. Strauss & Howe identify these periods as the “First Turnings” of a 4-part cycle.

The earliest of these First Turnings which S & H have identified covered the period of the rule of Henry VII in Britain, continuing into the first part of that of Henry VIII. The second such First Turning, initiating the next cycle, took place over the (late) reign of Elizabeth I and James I. A third started with the reign of Queen Anne and continued into the beginnings of the Hanoverian rule. [Note: after, but very soon after formal wizarding Seclusion was established.] In each of these, and in all subsequent “First Turnings” the general population numbers would have surged. Another characteristic of the First Turning is an expansion of the middle classes and an overall improvement in the quality of life of the general population.

It stands to reason that during each of these periods there would have been a larger number of Muggle-born wizards produced, but it would have only been with the lowering of the rates of infant mortality that took place over the 19th century that this factor would have become readily apparent, and increasingly significant.

Once wizarding Seclusion was established, however, these Muggle-born wizards were no longer necessarily being identified, taken under wizarding patronage, and diverted into the wizarding community. Particularly not if their parents had relocated away from the villages in which wizards still lived and could identify them. Consequently, any that managed to survive to produce offspring of their own would have been contributing a fully-operative set of wizarding traits to the local mundane gene pool.

Although it is difficult to try to summarize, persons in Muggle Britain who carry magical traits might make up as high a percentage as persons with an Rh- blood type. Which, in a population of some 60 million, at 15% would come out at around 900,000. It is tempting to extrapolate that this might be a workable estimation of those that might carry the Squib factor today. But probably a temptation that should be resisted.

In addition, every Squib that has ever left the wizarding community to make his fortune among the Muggles has also contributed an inoperative set of wizarding traits to the general population (along with the presumed Squib factor). Every young wizard out sowing wild oats among the barmaids, every undocumented Muggle-born Squib, has seeded the available breeding population with magical traits. Ever since wizards began. And, as I say, once the infant mortality rate began dropping in the 19th century, ever more of these carriers have been surviving to reproduce.

And even more to the point, ever since the Acts of Enclosure started forcing thousands of rural families off the land and into the towns and factories, all of these groups of people who might share the same suppressed set of magical traits with everyone in a ten mile radius of their home village had a vastly higher chance of meeting up and pairing off with someone from a different region who may be carrying a set of additional components. And eventually the Squib factor failed to be passed on.

It is also possible that by the mid-19th century the general population level and the wizarding [whether truly genetic or otherwise] material within it may have reached the critical levels necessary to start producing Muggle-born wizards on a comparatively regular basis in any case. Wizarding traits have been being recycled back into the gene pool for millennia, and Britain is, after all, an island nation. Its population has been inter-breeding from time immemorial, and if the indigenous folk mythologies of Great Britain can be trusted, wizards were never all THAT uncommon among the Celtic or Pictish tribes prior to the Saxon and Norse invasions. Nor were they unknown among the Saxons and the Normans, either, although they were rather less common than among the Celts and Picts.

Although these traits would have initially been submerged through dilution from successive waves of largely non-magical invaders (or, at any rate more magically-intolerant invaders), if these traits behave as Recessives, very few of them have actually been lost. By the late-18th century they may have finally perpetuated to the point that they were beginning to reestablish themselves within the mundane population of Great Britain. And except in a handful of villages, there were no longer trained wizards in proximity to identify them.

With the continuing overall rise of the population over the 19th and 20th centuries, the result has been that the births of Muggle-born wizards are steadily becoming more common. The Malfoy/Black et. als. faction actually has some grounds for feeling themselves under siege. Even though the walls were of their own building.

I postulate that there are at least a dozen or so different classes of basic magical traits, and possibly up to couple of hundred minor variations within these basic classes; and that an individual must inherit a minimum number of them (which may be as low as 1 or 2) before the subject will be psychically active enough to be capable of conducting Magic.

And, in addition, they must not inherit the Squib factor.

What is more, any individual subject might carry a LOT more than the minimum. Which would go a long way towards explaining how — possibly even in the absence of a Squib factor — some wizard/Muggle crosses consistently produce magical offspring while some others may not.

Returning to the continuing efforts of Human wizards to maintain the population levels necessary to hold onto their position of dominance among the loose confederation of magical Beings; to identify all magical births is only one part of the equation. In the same interview which gave us the age figures upon which most of us calculated the ages and dates of James Potter and his friends, Rowling also told us that wizards have far longer potential lifespans than Muggles.

This last is a claim which is not really reflected in Potterverse wizarding society. Rowling does not show us a society which boasts an exceptionally large geriatric population. She seems incapable of even showing us a plausible number of children with living grandparents. Only Neville Longbottom appears to be so blessed, and he possesses only a single grandmother. Under the circumstances, I have been forced to conclude that while extremely long-lived magicals such as Professor Griselda Marchbanks, or Bathilda Bagshott are not unknown in wizarding Britain, they are vanishingly rare. The usual projected (not actual, obviously) lifespan for wizards is probably somewhere in the range of 90–120 years. Longer than that of the average Muggle, certainly, but not to so significant a degree as to overbalance their whole society in favor of the aged.

That wizards are not shown in canon to have a correspondingly longer juvenile stage before reaching maturity suggests that this longer lifespan is at least partially granted as a side effect of the active channeling of magic. It is clear in canon that a child’s magic typically does not increase to the point of being reliably trainable until he approaches puberty. Ergo; it would only be after puberty that any apparent decrease in the rate of aging would be observable.

It should be noted however that there is some debate as to whether the apparent ages of the onset of puberty, as depicted in the series really reflects that of the present day. It certainly marches in tune with my own recollections in the mid-20th century, but we are no longer living in the mid-20th century.

It is certainly possible that any increase in wizarding longevity may simply be the result of a greater understanding of those factors which contribute to longevity in general, much in the way that such understanding of nutritional factors in the later 20th century affected the average height and longevity of Muggles. Or it may be a side effect of the medi-magical procedures which all but instantly eliminate most of the diseases which usually kill Muggles.

Such long lives also seem to be a potential which may be seldom realized due to the ww’s lack of effort expended upon the prevention of the various potentially fatal magical diseases which seem to plague it.

My interpretation of the way that magic works also allows for the possibility that the active conduction of magical energies (while employing the safeguard of a well-fitted wand and the indirect channeling methods of modern wizardry), may actively promote and preserve the physical well being of the wizard. By all indications, (and certainly all of the examples given in canon) any damage produced by the practice of what is nowadays classified as Dark magic, appears to result in a deterioration of one’s grasp upon reality which appears to have no corresponding component of physical degeneration.

Historically, I propose that such an afflicted wizard’s balance of mind eventually would have represented a sufficient danger to his family and neighbors that they would have been forced to restrain him, and typically this required his removal from society. We have no real information on the average lifespans of wizards in the days that all magic was Dark magic. The folk belief among some Muggles that wizards are actually immortal is probably based upon the rarity with which a known wizard was known to have died a natural death.

With the development of modern wizardry, shortly before the rise of the Middle Ages, I postulate that a wizard would be taught how to remove his psychic Self from the direct channel of the energies that he was physically conducting. Such a radically new procedure for conducting and directing magical energy meant that he was now able to get all of the physical benefit without the attendant risk of the deterioration of his perception of the world around him, and his place in it, which had previously been the case. Once so established, such a procedure meant that it was now safer for him to actually exercise his native conductivity to a far greater extent than it had ever been when such an exercise carried a corresponding risk to his psychic health.

In the days that all magic was Dark magic, a wizard might be able to acquire a great amount of magical lore without taking any harm, but, given that the actual practice of magic entailed a far greater exposure to the chaotic elements which accompany the flow of magic itself than modern methods, it was believed to usually end in madness. Consequently, most wizards actually conducted magical energy as infrequently as possible in order to extend their effective period of lucid productivity. Consequently, they did not derive the full potential physical benefit that the conduction of Magical energies can convey, even while they remained at full risk of whatever magical maladies might arise from being a natural conductor of such energies.

We have tacitly been told in canon that the ability to conduct magical energy matures with the wizard. Children are not typically given wands and taught to perform spells until they reach the age of 11 and are on the brink of puberty. We were also directly told by the false Mad-eye Moody in Goblet of Fire that a roomful of hormonal 14–15-year-olds would not be able to channel the amount of magic necessary to perform the Avada Kedavra curse. From this we can draw the conclusion that magical conductivity requires a degree of physical maturity to become fully functional. Magical children younger than those of an age to be given wands have been shown to be able to use charmed items such as wizarding toys, and to be able to channel some amount of magical energy through a wand, but until the ages of nine or ten, have only rarely been reported to have done what could be regarded as actually performing a spell.

Such reports do exist, of course. These incidents are not precisely rare, but neither are they common. I propose that the number and severity of the magical breakthroughs which plagued Harry Potter during his childhood were an extreme case and were dependent upon special circumstances further gone into in the article entitled; ‘Redeeming the Potterverse’.

In support of my contention that Harry’s case is unusual, I would like to direct attention to Dumbledore’s explanation at the end of Chamber of Secrets in which he shares with Harry his explanation of how Harry came to be a Parselmouth. If Voldemort did unwittingly transfer some of his own power into Harry on the night of his defeat (by whatever method), then we must conclude that since the age of 15 months, Harry Potter has been carrying at least some of the power of an adult wizard, (and a very powerful one at that) in addition to his own. This alone is enough to suggest one possible reason for why Harry’s childhood was so rich in breakthrough incidents.

I also offer the suggestion that it is not unheard of for a wizarding child (one who is not carrying more magic than he can reasonably be expected to control) to unconsciously learn to dissipate the magical energies that he generates so steadily that it rarely builds up to the point of creating a breakthrough — which a child might understandably find alarming. In fact that a significant minority, perhaps one in 20 to 50, wizarding children, either pureblood or Muggle-born, may have comparatively little history of such breakthrough incidents after reaching the toddler stage due to this ability. Such children probably need some additional time and/or tutoring to unlearn this habit of siphoning-off their magic when it comes time to engage in their magical education. Unfortunately, I doubt that they get it.

Other cases, such as that of Ariana Dumbledore, manage to block conduction of magical energies so successfully that when a breakthrough does occur it is devastating. Unfortunately we do not have the information necessary to draw truly informed conjectures regarding Ariana’s particular case. I personally am of the opinion that in addition to any assumed long-term emotional trauma, Miss Dumbledore may have also suffered from some form of seizure disorder dating from a head injury sustained in the attack upon her when she was six.

With the increased recognition of the physical benefits of channeling magical energy becoming more common, once the general adoption of the methods of modern wizardry had become widespread, practicing wizards would have begun to see an increase in their lifespans. I believe that by the end of the 15th century, wizards’ lifespans (like those of modern Muggles after the 2nd World War), had begin to be noticeably longer than those of their Muggle contemporaries.

• • • •

Given that the population decrease over the first century of Seclusion would have been a cause for much concern, a great deal of attention must have been directed toward the extending of a wizard’s effective life to offset the degree of attrition that the wizarding world was experiencing. It now seems unlikely that these efforts actually came to any great fruition.

Most of the population decline experienced over the first century of Seclusion would have been to some degree illusionary, since the greatest loss would have been that of all the mundane family members which had accompanied the wizarding world into its retreats. I think that after untold centuries of living mixed in among Muggles it had simply never been apparent to the wizarding population’s leaders just how small their numbers actually were. By the end of the first century of Seclusion all of the original Muggle family members of the community were gone, and even any second-generation non-magicals would have also been quite elderly.

What is more, most of the surviving original wizards would also now be quite elderly, and the larger percentage of them also would no longer still be alive. By this point, some hundred years or so after the establishment of Seclusion, the wizarding world would have been composed primarily of those who had been born during the Seclusion itself. Given that even in the current day the average Hogwarts incoming class appears to be something around 40 children, representing the entire number of magical births throughout Great Britain and Ireland for that year, of which only 25% are reported as being purebloods. It seems unlikely that a birthrate of what must have been not much more than a dozen births in an average year would have provided enough new members to sustain a viable society. It certainly would not sustain one at the level required to support the services which have been shown to be available to the wizards of today.

This expansion of services is likely to be due to the comparatively rapid increase of the wizarding population over the 19th and 20th centuries. Which has largely been dependent upon the increasing number of Muggle-borns recruited into the wizarding world, and the even greater increase in the numbers of the technical halfbloods who are their descendants.

Extending the total lifespan of its members could have only offset part of the problem, however, even had it been possible. When people’s lifespans have been extended they do not necessarily stay young (or fertile) longer. They typically — stay — old. Longer. This may slow the natural attrition of the group as a whole, but it does not raise the population in any sectors except those of the old, and of the very old. The developments that would be necessary to further the population’s numbers and general viability would be those necessary to extend the childbearing years of witches from its original level at the time that Seclusion was imposed. Which, based upon a lifespan of about a century, might have translated into a fertile period similar to that of a typically healthy and well-nourished Muggle of today; approximately 35-40 years. And, at the same time, to encourage larger families, ultimately spreading the population’s actual increase across all age sectors.

We do not know whether this has ever actually been either attempted or achieved. It certainly does not appear to be the case in the wizarding world today. From canon we can see that if average family size ever saw an increase within the wizarding world, that certainly is no longer the norm. Most of the children we meet in canon appear to be from fairly small families, and only children appear to be far from unusual.

However, if the childbearing years of modern witches are indeed longer than those of modern Muggles, some of these perceived only children may in fact have siblings of an entirely different Hogwarts generation, rather than being a part of a Weasley-style family of siblings who are all as close in age as in a large Muggle family. We may speculate, at least, that among witches, a pregnancy in one’s mid-40s might be regarded as no more dangerous than one in one’s 20s. But it is quite likely that, as among Muggle women, a witch’s basic fertility level begins to decline some years in advance of actually reaching menopause. This would tend to encourage the bearing of one’s children before leaving one’s 30s.

• • • •

It is also all too likely that there may be a physiological reason for the rarity of families with large numbers of magical children as well. This issue is touched upon in the companion pieces, ‘Wizards & Muggles: Pre-& Post-Seclusion’. A portion of which has been extracted and repeated here:

I have my own pet theory regarding the manner in which the charmed Hogwarts quill actually works. I propose that the reasoning that went into its development progressed along something like the following lines:

Reasoning from the starting point that; although it had long been observed that all magical children do not have an extensive history of magical breakthroughs, the generality is that they all experience at least a few of them. Particularly in their earliest infancy before that afore-mentioned minority learn to unconsciously dissipate the magical energies which cause them.

Allowing this premise; at some point in the R&D stage, one of the project’s development team — probably an ex-Ravenclaw — followed that line of reasoning to its logical conclusion and hypothesized that;

If the younger a child is; the more likely he is to be unable to suppress a magical breakthrough, AND;

If the greater the [child’s perception of] danger/stress/fear/pain to which such an immature wizard is exposed; the more likely he is to generate such a breakthrough, AND;

The more immature a child’s nervous system is; the smaller the amount of Magical energy that can actually be channeled by such a breakthrough, THEN; IF;

The most likely experience held in common by all infant wizards capable of generating such a breakthrough is the stress/fear/pain undergone during the birthing process itself; THEN;

What the project’s developers are looking for are very low-level breakthroughs which channel very small amounts of Magical energy within a specific range of frequencies.

• • • •

However: such breakthroughs, however small, can hardly be conducive to an easy birth. While, by this time, there are probably medi-magical procedures designed to lessen the risks attendant to both infants and mothers by such natal breakthroughs, which may now be routinely employed by Healers and midwitches it is quite possible that the lack of such procedures may have been a major contribution to the low family sizes generally believed to be prevalent within the wizarding community until fairly recent times (this perception appears to have been somewhat contradicted by the information on the Black family tapestry sketch released in February 2006 in which the average family size over the past 150 or so years appears to have usually produced three children).

It is certainly not beyond the reach of possibility that such a natal breakthrough may have contributed to the death following childbirth of Merope Riddle, née Gaunt; who gave birth to what is generally presumed to be an exceptionally magical child with no more assistance than that which was available through the mundane birthing practices of 1926. However, now that we actually have the official Riddle backstory, it seems blindingly evident that Merope’s death was most probably due to a profound failure of the will to live.

While it is obvious that to birth a magical child does not usually result in the death of a witch, it is possible that until comparatively recently, it might well have sometimes resulted in such internal injuries as to make future children a remote possibility. While a fair number of current wizarding families (apart from the Weasleys) appear to have two or more children, there also appears to be a fairly high representation of “only” children among Harry’s current schoolmates, both wizard and Muggle-born. Although our sampling on that regard is likely to be somewhat skewed due to the high number of war orphans in Harry’s age bracket, and Harry’s own general lack of interest in his fellow classmates.

It might be interesting to know whether this appearance is in fact, accurate, and whether this is a recent, or a long-established trend. But the fact that a high number of these only children are being raised by a single parent, or a parent and step-parent, or a grandparent, and their only child status is due to the events of VoldWar I cannot be overlooked.

• • • •

It has is also been recently suggested that by the late 20th and early 21st century, a few Muggle-born wizards may now be falling through the cracks due to caesarian intervention having been implemented before the child has been subjected to sufficient stress necessary to cause the Magical breakthrough which is required for his birth to be registered as magical by the Hogwarts quill (or those of the various European Ministries of Magic, if any). Such a child’s subsequent neurological development would soon render any breakthroughs that he produced outside the range of frequency that such quills are calibrated to recognize. Such a situation may be the explanation for some of the rare, “late bloomers” which have allegedly been noted in recent years (i.e., interview statements that never materialized in the actual books). We have no example of such instances within the official canon.

It is, at present, unknown whether any medi-magical procedures intended to extend a witch’s fertile period have in fact been developed or are in fact being utilized. At present we have been given no information that would support this reading. It is quite possible that the early marriages which have been implied in canon may be socially encouraged out of consideration of the lack of such procedures. In which case we may also assume that the magical Academies of the wizarding world today still serve a secondary function in the capacity of a matchmaker’s service. The collection of genealogical references in the Hogwarts Library (those “books of wizarding families” which young Riddle used to finally trace the identity of his grandfather, Marvolo Gaunt) would tend to suggest such a purpose.

Whether this is the case or not, what appears to be incontestable is that until the wizarding world is able to produce and maintain a population in which the young are not grossly outnumbered by the old, neither their continued existence nor their dominant position among the ranks of Magical Beings will ever be truly secure.