Subject: There's a lot of ways it could work, really
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Posted on: 2009-05-20 22:50:00 UTC
and strangely it's questions like this that make me wish I was better at genetics, rather than, say, the desire to have got better marks in it in undergrad :P
I'm betaing a Harry Potter/Stargate crossover for someone and we've been discussing the ATA gene and if it has an effect on HP magic or not/controls HP magic or not. She came up with this and asked if this was sound. From what I can understand, it seems to be, but I thought I'd get a second opinion (obviously, this is directed mostly at Trojie, goddess of biology). In case you're not familiar with Stargate, the ATA gene (does that actually stand for anything?) is what gives people the ability to control Ancient/Alteran technology.
"There are three general principles that are the basis of this theory.
1. Either you have a gene, or you don’t.
2. The expression of genes you do have can be strong, weak, something in between, or even non-existing.
3. Promoter genes are genes that tell other genes if they should be turned on or off, and how strong their expression should be.
Keeping that in mind, if you look at the ATA gene, you either have it, or you don’t. If you don’t have it, you cannot turn on, or in some cases even control, Ancient technology. If you do have the ATA gene, the expression can be different. O’Neill, Beckett and Sheppard, for instance, have a very strong expression.
The ATA gene has shown no sign of being recessive, so I’m considering it as a dominant gene. It is, however rare, and needs some promoter genes to work, which is the reason the gene therapy works for McKay, but not for everyone. McKay has the necessary promoter genes to turn the gene on, while others don’t have it, so the gene therapy doesn’t work on them. The promoter genes are passed on separately from the ATA gene, so active ATA genes are not always heritable.
All magical people, and that includes most Squibs, have the ATA gene, but in order to have working magical abilities, they need to have an additional, dominant gene, which I’ll call the MAG gene. Squibs, born from two magical parents, do have the ATA gene in most cases, but lack the MAG gene, so they can’t do magic. Muggleborns have one parent with the ATA gene, while the other has the MAG gene, and they have inherited both, enabling them to do magic while their parents can’t. The fact that Wizards need both rare genes to be magical accounts for the very low number of magical people on Earth.
Magical ability is correlated with the expression of the MAG gene, just like the strength of the ATA gene is correlated with its expression.
In my story, Daniel has both the ATA gene and the MAG gene, with a moderate ATA gene expression and a strong MAG gene expression (like Harry had before the merging). Jack doesn’t have the MAG gene, but he does have the ATA gene and it is expressed very strong."
*isn't sure how to start with this*
I may be mildly incoherent in this explanation, so if I'm unclear, do ask.
Um, okay. Genes. Right.
Genes are lengths of DNA. DNA is read from one end to the other, so they have to be in the right order to work correctly. DNA condenses into chromosomes, which come in pairs. Each member of a pair has the same genes (well, theoretically, but we won't go into crossing over and mutations and things here) because they are copies of each other. So you have two copies of each gene.
There may be two or more slightly different versions of a gene - these are called alleles. It is alleles that are either dominant or recessive, not genes.
So, the way I interpret what you're talking about is that the ATA gene has two alleles - dominant (= can use Ancient tech) and recessive (= can't use it). If someone is homozygous dominant (that is, they carry two dominant alleles), they have the 'strong' expression of the gene (= phenotype). If they are a heterozygote (have one copy of each allele) they have a more moderate expression. Someone who is homozygous recessive is not able to use Ancient tech - they are a 'normal' human. As is the case with blue eye colour, it is very possibly for the recessive allele to be more common in a population.
The promoter gene would be heritable in the same way, and the MAG gene as well.
Basically her theory follows, but with the modification that genes themselves are not dominant or recessive; that it is their different forms that are :)
Or at least, it works enough for fiction - a real geneticist, which I am not, would most likely kick up at the details, but then again, they'd probably kick up about Ancient technology and about magic as well :P
and I totally agree.
I would have thought MAG would be a downstream gene from ATA (which would be involved in two different, but similar, functions: using Ancient technology, and using magic, though the MAG gene). But any way could work.
and strangely it's questions like this that make me wish I was better at genetics, rather than, say, the desire to have got better marks in it in undergrad :P
I, of course, had no idea what you were talking about, but I'm sleepy, so I may understand later on.
I'll give her the link here. She should understand as she is "studing biology and [has] an exam about genes and gene expression in about ten days...."
That part is sound. I understand that in the story the MAG gene is a sort of promotor gene, and that magic is actually a form of Ancient way of operating technology.
As put here, I think the latter part is sound too.