Rachel Neumeier

Fantasy and Young Adult Fantasy Author


Black dog genetics

My brother commented recently that I must have worked out the genetics behind the black dogs and Pure in detail — which is true! And actually, a reader asked about it, though she might not *really* want to know *all* the details. But hey! For those of you with esoteric interests, or anybody who just wonders, I thought I’d lay it out for you, semi-briefly.

Actually, this is *very* brief, considering the file I have on this is about ten pages long! But here is the short version:

Okay, the black dog “trait” itself is quite simple, a straight-up no-frills two-allele system where the black dog allele, which I will call “B”, is dominant. Well, the trait is not actually perfectly simple, because a BB homozygote will generally have a stronger shadow than a Bb heterozygote, so you could say it is an incomplete dominant — but essentially everyone with a BB or Bb genotype will be a black dog. A stronger shadow is not a good thing, by the way, since a strong demonic shadow tends to “eat” the original human personality. Also, remember that there is significant supernatural influence on this trait, which messes up normal probability, so that if a human woman bears children to a black dog man, with every pregnancy, the child is more likely to be a black dog.

You know, of course, that there has been a lot of demonic influence behind the scenes in the BLACK DOG world. So perhaps it won’t surprise you to learn that many people carry a genetic resistance to demonic influence. For all I know, there may be more than one such trait, but the one that concerns us is the X-linked E/e series. The recessive “e” allele confers some slight resistance to demonic influence of all kinds. The vampire miasma was always quite effective, but never quite complete enough to prevent some knowledge of vampires and other demonic creatures from “leaking out.” People with the XeXe and XeY genotypes were the ones responsible for this. (Sorry, WordPress doesn’t seem to want to let me do superscripts.)

Okay, now, suppose a Bb XeY (black dog man) has a child with a bb XEXe woman (human). Unfortunately, there is demonic pressure against the “Xe” allele being passed on, so that there is a pretty good chance the child will get the “XE” from the mother and a REALLY good chance the child will get the “Y” from his father. This is one primary factor that leads to the preponderance of black dogs being male.

Now, the Pure. As you know, Saint Walburga (or Vaubourg, or Waltpurde, or Gauburge) did the magic or channeled the miracle that led to the creation of black dogs the Pure. This was around was 740 AD, so it was some time ago. Whatever she did, the effect was to create a new allele (at an unlinked locus) that confers a different and stronger kind of resistance to demonic influence. Call it the “r” allele — or actually the “rp” allele because it leads to the Pure. Sorry for the lack of a superscript. The plain “r” allele was the “wild type” and confers no resistance.

Now, it turns out that IF you are genetically a black dog and IF you line up enough “resistance” alleles, you wind up Pure. Unfortunately for guys, “enough” is four, and even then it’s only enough if you’re working against less-powerful shadows. The only genotype that creates a Pure individual is Bb rprp XeXe. This is why the Pure are so rare, and it’s also why the Pure are always female. However, a black dog with a genotype such as BB rprp XeY will have plenty of strength AND vastly enhanced control over his shadow. This is Ezekiel’s genotype (but even for this genotype, he is also on the extra-cool end of the probability curve). Probably quite a few Dimilioc black dogs have a similar genotype.

Now, if you look up Saint Walburga, you’ll find that she was born in England but spend a large chunk of her life doing important saint-type things in Germany, so that is why the first black dog houses that really made use of the Pure were founded in those countries. Their influence spread, so there were actually quite a handful of such black dog families in Western Europe for a while there, and of course Dimilioc emigrated to North America, but as you know a whole lot of black dogs were killed in the war. It’s not clear yet if enough black dogs with this kind of heritage are left to reconstitute any of the European houses.

What the Dimilioc black dogs don’t know — what, in fact, no one knows except me (and now you) is that a second “create the Pure” miracle happened elsewhere in Europe at about the same time or perhaps a bit later — in Moorish Spain, almost certainly in the Jewish population. This new allele is also part of the “R” series, but it’s not the same as the “rp” allele. If you’re working with the “rp” allele, you need four “resistance” alleles to create a Pure genetype, but if you’re working with the “R” allele, you only need three. The “R” allele wound up significantly more widespread than the “rp” allele, because it was carried into the Middle East by the Spanish Jews and into Latin America and elsewhere by other people of Spanish extraction. But the “R” allele is far less concentrated in any one population than the “rp” allele, so RR homozygotes are quite rare.

There are, however, ten genotypes involving the “R” allele which could lead to a Pure individual being born: Bb RR XEXe , Bb RR XeXe , Bb RR XeY , Bb Rrp XeXe , Bb Rr XeXe , and the same again only homozygous for the BB allele.

Not only is the “R” allele more epistatic to the BB genotype than the “rp” allele, able to create the Pure even from a BB genotype, but also it may be the case that the Pure might be more able to work with black dog magic if they possess an “R” allele. Who knows? Maybe that explains certain things about Natividad and her mother. Plus, you can see that there is a chance of getting a Pure guy if he is really lucky and gets an “R” allele from each parent, plus an “Xe” from his mother, plus at least one “B”.

Anyway, the “R” allele can yield substantially better outcomes than the “rp” allele ever managed on its own, so it’s too bad Dimilioc doesn’t know the genetics behind all this and can’t go deliberately seek out that kind of Pure. However, they’ve lucked out in Natividad, who got the “R” from her mother and the “rp” from her father and whose genotype is either Bb Rrp XEXe or Bb Rrp XeXe, or the same only homozygous for BB.

Now, aren’t you glad you know all that?

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6 Comments Black dog genetics

  1. Elaine T

    “Now, the Pure. As you know, Saint Walburga (or Vaubourg, or Waltpurde, or Gauburge) did the magic or channeled the miracle that led to the creation of black dogs.”

    Don’t you mean the creation of the Pure?

    Thank you for this explanation. I’d been wondering if I wanted to ask you via e-mail how it came about that there were Jewish Pure, or just how they got so widespread from one person originally, when she apparently became a nun (hence celibate). AND what made Natividad and her mother different because you’re not the sort of writer to have done it just ‘because’ for story purposes.

    Now, I’m also puzzling over the existence of an old Catholic church building in Protestant Vermont. :-) I guess my speculation that not all black dogs are wholly demonic is not going to pan out, though.

  2. Rachel

    Gosh, yes. Oops. I’ll have to go change that.

    Hey, according to Wikipedia, there’s a substantial Catholic population in Vermont! If you can’t trust Wikipedia, who can you trust?

    Also, as you’ve probably realized, St. Walburga wasn’t a black dog or Pure. She created — or channeled a miracle that created — a Pure child when the child ought to have been born a black dog.

  3. Elaine T

    Yeah, I remember that. Why I said the original Pure person became a nun was from the scene where the Calming’s origin comes up. St. Walburga developed it with the first Pures who had become nuns. So I figured she channeled more than one miracle to get more Pures. Saints do tend to have specialties, when it comes to miracles (I’m Catholic, and read a lot) so It’s plausible. But even back then, nuns were supposed to be celibate.
    Or the first one grew up and had enough Pure babies to have some be nuns and some marry and have lots more children carrying those genes. And some of those, once widowed, joined the monastery and helped St. Walburga develop the Calming. Actually, I like that idea … they’d have been out in the world living with Black Dogs and inventing ways to help them, after all.

  4. Diana

    I have to ask, because I suspect you have thought it through.

    Does the demonic selective pressure exert itself during the chromosome line up of meiosis or via an increased chance of resorption of offspring before implantation? Fertility affects could differ depending on whether it affects gametogenesis or implantation. Sounded like that might be where you were headed (gametogenisis). If any Xe carrying sperm are created, technology could be used to find and selectively fertilize with rare Xe sperm only. If demonic selection pressure is post fertilization, then not going to help. Though having a Pure protect a newly pregnant female might.

  5. Rachel

    Wow, quite a question! I had thought only about effects during gametogenesis and meiosis, but in fact that ought to only influence the black dog (whom we will assume here is the father), never the mother. So I’m thinking a post-fertilization process must also be working in order to also skew the probability of what allele gets inherited from the mother.

  6. Rachel

    Oh, did I say that? In that case I hereby declare the miracle was rather widespread and affected more women than anyone realized.

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