Genetic Components of Metamorphagi

[OliveOil_Med]

I have been wondering a great deal of thinking about Metamorphagi lately, and I have a good idea of just how rare they are. But I do have other ponderings on the topic.

We seem to have a good understanding of the genetic components of a Muggle-born wizard, but now I wonder about the genetic components of a Metamorphagus. We know that a Metamorphai doesn't need to be a pureblood witch or wizard, but can a witch or wizard with a Muggle parent possibly be a Metamorphagus?

Someone who has done a great deal of study in genetics would be really helpful. I assume the gene for the abilities of a Metamorphagus are either recessive or carrier. Do you think the fact that Tonks herself is a Metamorphagus increased the chances of Teddy being born with the ability? Does anyone know of any genetic illnesses I could study that you think would be at all similar to this ability?

[Tim the Enchanter]

Do you think the fact that Tonks herself is a Metamorphagus increased the chances of Teddy being born with the ability?

I know next to nothing about genetics, but I would assume that Tonks being a Metamorphmagus increased the chances of Teddy being born with the same ability.

However, we must take into account how often the trait is passed down from each generation. If all that was required to be a Metamorphmagus was to have one parent with the trait, then this ability would be far more common than described in the book. I suppose Teddy is a unique case, in which he became a Metamorphmagus not just because of his mother, but also because of Remus, who might have something in his genes from being a werewolf about changing body shape - but of course, that opens the debate on whether Lycanthropy does anything to your genes or not.

Anyway, I would personally be wary of trying to apply genetics to the wizarding world of Harry Potter. Trying to quantify magical properties generally seems to be an exercise in futility.

Tim the Enchanter

[OliveOil_Med]

Maybe it doesn't have anything to do with dominant or recessive genes. Maybe it's more like a gene mutation.

I know of a genetic disorder called Williams Syndrome that is cause by a genetic mutation, and it is only genetic when one of the parents has the disorder. This could be a possibility, but then I think it would just make for Metamorphagi being a lot more common.

Maybe having a Metamorphagus for a parent just increases the likelyhood of the gene mutation, but nothing is for certain.

[Karaley Dargen]

However, we must take into account how often the trait is passed down from each generation. If all that was required to be a Metamorphmagus was to have one parent with the trait, then this ability would be far more common than described in the book. I suppose Teddy is a unique case, in which he became a Metamorphmagus not just because of his mother, but also because of Remus, who might have something in his genes from being a werewolf about changing body shape - but of course, that opens the debate on whether Lycanthropy does anything to your genes or not.

I agree with you that it could have something to do with Lupin, but I doubt it has anything to do with his Lycantrophy. Teddy seems to be fine in the werewolf-department, and I doubt that being a werewolf would change Lupin in his stem cells. However, maybe there was a Metamorphmagus generations back in Lupin's family - similar to how it's possible that there were wizards generations back in the family of a muggleborn. Then, if the gene was recessive and only came to show if there was some trace of it in both parents, that would explain why it happened with Teddy - and why, apparently, none of Tonks' parents are Metamorphmagi, but she is. I don't have names of any specific illnesses here right now, but I'm almost 100% sure that there are illnesses that require both parents to carry a certain gene. It wouldn't show in them, because one of their parents (the child's grandparents) didn't have it, but since the parent-generation both have it (and the requirement of that being the case slims chances of it actually happening down A LOT), the "results"/symptoms show in the child.

Trying with an example... Lupin's paternal great great great great grandfather (I'll call him F from now) was a Metamorphmagus; his wife, however, was not, and no one in the Lupin family met/married a Metamorphmagus from then. However, all the descendants of that F had the gene to potentially produce a Metamorphmagus. (and, of course, the other way round, the gene must have been in the family before F)

Ted Tonks had another ancestor who no one ever knew of, who was a wizard and also a Metamorphmagus (let's call him G). Also, Isla Black's maternal great great grandmother (yeah that's some old woman we're talking about, and she's called H) was one. Now, since none of their offsprings' offsprings ever married/had a child with another M-gene carrier, the Metamorphmagism didn't show in their families for a long time, and probably no one even knew by the 1970s. However, when the descendants of H and G - who both carried the recessive gene - had a child, Tonks got the gene from both sides, and turned out a "true" Metamorphmagus. And then the same would go for her and the offspring of F. But you see how extremely unlikely it is that something like that would happen - the descendants of two RARE Metamorphmagi meeting, AND having a child?

I don't know if that is how JKR would explain it... maybe it's more of a chance thing, like if you are one, you have a 25:75 chance that your child becomes one too...

[OliveOil_Med]

Yes, it is very complicated, but I simply cannot let it go. That is why I find myself pondering if it has more to do with a gene mutation after conseption as opposed to inherited genes.

Any other thoughts or ideas?

[OliveOil_Med]

Double-posting because I have something else I have been wondering about when it comes to Metamorphagi.

Do you think a person needs to have two wizard parents in order to be a Metamorphagus? The only instances we have seen of this comes from wizards with two wizarding parents. But what I wonder is if it possible to have a Muggle-born Metamorphagus, or a Metamorphagus born to a wizarding and a Muggle parent?

If Metamorphagus abilities were gene-based, then it would probably only be for two wizarding parents, but if it is cause by a gene mutation, then the later could be possible.

[circlemidnight]

I thought it's possible to have a mentamorphagus from squibs, since they have magical genes, but dunno about muggle-born squibs

[MorganRay]

We know that a Metamorphai doesn't need to be a pureblood witch or wizard, but can a witch or wizard with a Muggle parent possibly be a Metamorphagus?

If the gene to be a Metamorphai is a simply Mendalian genetic trait, then yes, this is plausible. However, maybe the gene needs a magical component (another gene?) to be active. Complex genetic traits (think height and weight) are really common and involve environmental factors as well as genetic factors. Some complex traits (height) rely less on environmental factors than other genetic traits. Also, development is all about certain genes being activated or repressed to make various proteins depending on what hormones and signaling molecules are available in the developing embryo.

I assume the gene for the abilities of a Metamorphagus are either recessive or carrier. Do you think the fact that Tonks herself is a Metamorphagus increased the chances of Teddy being born with the ability? Does anyone know of any genetic illnesses I could study that you think would be at all similar to this ability?

This question is actually easier to answer than the first from a genetics standpoint. I think your first assumption of recessive or a carrier is probably the easiest one to make. I would say Tonks is a recessive carrier. It's probably easiest to think of a Metamorphai gene as a single gene trait (one gene codes for one trait) that follows simple, Mendelian rules (think Punnett squares). There are plenty of human petigrees available that show the lineage of carriers of recessive traits. Sex linked (X chromosome) recessive traits tend to be fairly common, and this is how hemophelia is transmitted. The really famous hemophelia lineage is of Queen Victoria and the royal family. The most important thing about an X chromosome linked recessive trait are these things: 1)the trait is rare and 2)only male progeny can inherit it. If Tonks is double recessive for whatever gene goes with becoming a Metamorphagus, then ALL her sons will be Metamorphagus, but none of her daughters will be. You should also assume Lupin doesn't have this trait because it is rare.

I agree with you that it could have something to do with Lupin, but I doubt it has anything to do with his Lycantrophy. Teddy seems to be fine in the werewolf-department, and I doubt that being a werewolf would change Lupin in his stem cells.

Yup. This sounds correct. Lupin's somatic cells are infected, but his germ cells seem to be fine (aka his sperm). It's like cutting off your finger. Your children won't inherit it, but you're always going to be minus a finger.

Then, if the gene was recessive and only came to show if there was some trace of it in both parents, that would explain why it happened with Teddy - and why, apparently, none of Tonks' parents are Metamorphmagi, but she is. I don't have names of any specific illnesses here right now, but I'm almost 100% sure that there are illnesses that require both parents to carry a certain gene.

I wrote about X-linked recessive traits, which are linked to the sex chromosomes (specifically, the X chromosome since Tonks is a Metamorphagus). However, if the trait is a somatic recessive single gene trait (it's a recessive gene that codes for one discrete trait on some other chromosome besides the sex chromosomes), then you have to make different assumptions. First, Lupin has to be heterozygous for the trait. This DOES NOT mean that a grandparent or former family member has to have carried the trait. Second, Tonks must be homozygous recessive for the trait. Third, assume it is just one gene coding for one trait and this follows simple Mendelian genetics. Therefore, Tonks and Lupin have a 1:1 chance of producing a Metamorghagus child of EITHER sex.

Trying with an example... Lupin's paternal great great great great grandfather (I'll call him F from now) was a Metamorphmagus; his wife, however, was not, and no one in the Lupin family met/married a Metamorphmagus from then. However, all the descendants of that F had the gene to potentially produce a Metamorphmagus.

None of the family members in either Tonks or Lupin's families had to be a Metamorphmagus prior to Tonks or Teddy being a Metamorphmagus. First, the trait is rare, so this means that the majority of the population is probably homozygous dominant or completely normal. However, what Lupin DOES have to have is one dominant and one recessive copy of the gene (he must be heterozygous). This applies to Tonks's parents as well. They BOTH must have been heterozygous because you cannot have a homozygous recessive child with one parent that is homozygous dominant. If one parent is homozygous dominant, ALL the children will be normal because they all inherit the dominant allele from the one parent.

Along the lines of diseases that work this way, there are plenty. Sickle cell anemia, Tay-Sachs, and cystic fibrosis are single gene traits that are all somatic homozygous recessive.