Mutations

[jack]

X-Men

In the X-men films Wolverine said the x-gene is passed on by men. I assumed this was just him yanking the parents' chain: after all, he's a memory-loss ex-cage-fighter posing as an art teacher, he might not know himself.

The films didn't have enough breeding to make it clear how it is inherited, but we infer (a) x-children are born to normal parents and (b) children of one or two "mutants" are more likely or certain to be so themselves (c) male and female "mutants" are equally likely.

Would the male thing be possible? Forgetting genetics, is it logically possible?

1. There can be male-line-only genes. Eg. genes that cause women to be infertile. However, it seems these would have a tendency to disappear, as your son's sons will have a 1/4 chance of inheriting their mother's and grandmother's genes at that point on the chromosome.

2. That *could* be the mechanism. Suppose a large number of such genes, and the absence of any causing "mutants". However, you'd expect an explosion in their population once they start to appear.

3. You might contrive a method whereby "being the father of mutants" was inherited in a normal through-both-lines way, say when you get two of a recessive gene, and only when you have that quality, and only through the sperm, can some actual mutant genetics be passed on. But I don't know how you'd arrange that biologically.

4. Or there might be a male only gene, a number of male lines of potential mutants, which is only expressed when some environmental factor is met. But that doesn't feel like it was inherited directly from the father, that the chance of the extra factor was more involved.

Did the comic books specify anything differently and more precisely than the films?

Can anyone improve on my genetic ramblings...?

Heroes

I was going to comment that it seems like children are special if and only if both parent are. And that's most likely explained by a recessive gene for specialness[1], and the chance that all the examples we've seen have been from both parents being special, rather than carriers.

But wondered if there's anything that can only be inherited from both parents. It seems awkward -- how the hell would it get started?

But I've run out of space and time[2].

[1] And a parcel of other genes that determine the kind of specialness, if that specialness is unlocked.

[2] As it were.

Comments

[ravingglory.livejournal.com]

Men have a Y chromosome, women don't. So if the "x-gene" was on the Y chromosome only men could pass it on. Of course then only men could express the gene, which doesn't seem to be the case.

Another possibily is gene imprinting. After miosis genes are metholated, which effect their expression latter. Genes are metholated differntly in males and females. So some traits are only active if you get them from your father, or conversy form your mother. (e.g. Male patern baldness only turns on if you get it from your mother)

However I thing all of these traits are far too complex to be controlled by a single gene, and there ought to be a lot more "almost superheroes" that are tottally messed up.

[cartesiandaemon.livejournal.com]

Another possibily is gene imprinting.

Ah, that's an interesting thought. There's a whole bunch of ways inheritance can happen other than just dominant/recessive as taught in school biology, I didn't try to get into having no idea how it might apply. That one's interesting.

However I thing all of these traits are far too complex to be controlled by a single gene, and there ought to be a lot more "almost superheroes" that are tottally messed up.

LOL. Well, yes.

But then, that's the premise of the series, if you required that to be accurate, you just wouldn't have a series at all :) So I'm determined, in face of the evidence, that the mutations either make you so unworkable you're never born, or give you something somewhat controllable.

To be fair to heroes, it faces this a little bit. The powers aren't anywhere near as random as chance would dictate (most of them are defined by the boundaries of bodies or objects!) but there is a sense of being dealt a power and it might not be tidy or good for you.

[zebbiejohnson.livejournal.com]

Lots of horrific diseases only appear in their bad form if inherited from both parents, it gets started by random mutation and a single-gene copy not killing you/preventing you breeding (usually be being functionally invisible, as the actions of the healthy gene copy compensates for the lack of the second one).

[zebbiejohnson.livejournal.com]

http://tom.idealog.info/blog/20030504-1052100570.shtml

[cartesiandaemon.livejournal.com]

Ah, thank you. I thought "non-biologists [should] never say never" was a good point -- that really applies (imle), even more than physics, etc.

Lots of horrific diseases only appear in their bad form if inherited from both parents,

Agh. I got all that the wrong way round. Of course, a simple recessive gene would exhibit "you have to get it from both parents". But all the examples given had:

(1) both parents were actually special, not just recessively special
(2) no normal children of special parents

Of course, those come from narrative causaulity. And are a small sample size anyway. But I like to pretend otherwise, which makes both a requirement, which I think becomes contradictory...

[despotliz.livejournal.com]

If the gene is passed on by men only, then it has to be a Y-chromosome gene. There is no difference at the DNA level between the X chromosome from your mother and the one from your father, as in females one of them is randomly inactivated anyway. And if it was a Y-chromosome gene, it would only be active in males, so you'd only get male mutants. So that's not really possible.

ravingglory's theory of gene imprinting makes much more sense - methylation of genes silences them, so it could be that all the copies of the gene in females are silenced by methylation.

Unltimately, though, you can't really explain the genetics of either X-Men or Heroes by conventional genetics, and it tends to make my brain hurt to even try, especially if Mohinder has been wittering on about evolution in his crap voiceovers again. S2 starts to muddy the waters of how powers are passed on *even more*.

[cartesiandaemon.livejournal.com]

If the gene is passed on by men only, then it has to be a Y-chromosome gene.

Though see my "makes women infertile" theory...

Unltimately, though, you can't really explain the genetics of either X-Men or Heroes by conventional genetics, and it tends to make my brain hurt to even try

Oh yes. I'm amused enough to try this sort of thing, even though it just doesn't work like that.

especially if Mohinder has been wittering on about evolution in his crap voiceovers again.

Oh yes, that too. I find that they sound impressive, whilst not actually meeting common sense at any point.

S2 starts to muddy the waters of how powers are passed on *even more*.

*sigh* I suppose I don't want to know. Both because I don't want spoilers (though that'll become a lost cause at some point) and because I don't want to imagine it's not going to be good.

(To be fair to them, so far, we've just seen super-parents with super-kids. Assuming that it was an if-and-only-if proposition was just my whim. Inheritance is sufficiently complex there's nothing implausible at all about the inheritance patterns. (The technobabble and concept, yes, but what else is possible?) For that matter, even in X-men, I never thought Wolverine's comment was at face value, even though I wondered what would be the case if it were. X-men is implausible in LOTS of ways, but the films never actually showed anyone inheriting anything from anyone, except that mutants can come from normal parents, which is necessary.)