Well thanks a lot Chance. Your wife made your head hurt, and now mine does!
I thought the “m” mean it came from her mother?
So how come Rogue is an X-woman? This isn’t adding up right for me. Is there an error in here somewhere?
Sadly, I haven’t seen X2, so I’m going to spell out the info I’ve been given:
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Both men and women can be mutants
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Only male mutants can have mutant offspring
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It hasn’t been established, but lacking other information I will assume that female mutants can have normal offspring.
How can this be?
Well, as has been previously established and with which I concur, the relevant DNA must certainly be found on the Y-chromosome. Some of the DNA, anyway. Since there are female mutants it’s obvious the mutant package may express itself in either gender and so is not found on the Y chromosome.
Luckily, that’s not the question. It’s a matter of reproduction. One scneario that comes to mind is thus: mutant cells, even unfertilized eggs with mutant genes, will express mutated proteins on their cell walls. I suggest the possibility that these proteins may interfere with some part of the pre-fertilization reproductive process. Maybe they prevent fertilization. Maybe the follicles fail to rupture in the ovaries. Whatever the precise cause, the net result is that the mutant genes cannot be present in the unfertilized ovum.
The obvious objection to this is to ask how two mutants can have mutant children. The answer is that the mutant genes must have come from the father and the genes the mtoher passe don must have been normal.
If this hypothesis is true, then 1) the mutant genes are dominant and 2) a mutant may only have one set of mutant genes, never two (There’s a word for that and it has totally slipped my mind). 3) A mutant male should have a roughly 50% chance of fathering a mutant - though that may vary depending on the dispersion of the mutant genes throughout the genome 4) A mutant female and a normal father can only have normal children.
Now let’s get some mutants to test this.
I thought I was a fairly intelligent person but this whole thread has left me even more confused. Can someone give it to me bluntly, was **Chance ** right or was **Lady Chance ** right?
Wow, resurrected thread after a month. Yeah, there is an error, my bad. I was less than clear on my last Punnett square post in this thread. When I drew the Punnett square, I was refering to the germ line of each of the X-men mating, not the autosomes. What Rogue and Wolverine’s germ line’s look like is irrelevant to the rest of the body, which determines X-man versus normal.
I failed to differentiate between Rogue’s body (which is A[sup]p[/sup]a) and her gametes – the imprinting is reset in her oocytes and therefore creates A[sup]m[/sup] and a gametes).
Only the presence of an A[sup]p[/sup] in your body will lead to X-manism. A[sup]p[/sup] results from inheriting an A allele from your father. So Rogue, producing A[sup]m[/sup]a primary gametes, will never produce an X-man in a mating with a normal male. The imprinting type (A[sup]p[/sup] versus A[sup]m[/sup]) in your autosomes of your body are only dependent on which parent you inherit the allele from. The allele that you produce in your germ line is only dependent on your sex. Therefore, if A[sup]p[/sup] is causing X-manism, both males and females can be affected but only males can pass it on.
Plain English. As best as I can do.
Variations of genes are called alleles. For every gene in our body, save those on the X and Y chromosomes in males, we have two alleles. Sometimes these alleles are the same, and we call the individual a homozygote for that gene. When a person has two different alleles, we call them a heterozygote.
There is a weird phenomenon in genetics called imprinting. For some genes (and for some alleles of some genes), it matters if you inherit the allele from your mother or your father. Sometimes, an allele inherited from your father will cause a mutant phenotype, while the same allele, if inherited from your mother, will do nothing, and sometimes vice versa.
Because of this, having the mutant allele, showing a phenotype, and passing on the mutant phenotype to your children become unrelated. If your father inherited his allele from his mother, he will not be an X-man. If your father inherited his allele from his father, he will. Likewise, he can pass it on to you and you can be an X-man, irrelevant of whether you are a boy or a girl. If you are a boy, you can pass it on to your children. If you are a girl, you will not.
The easiest way to make the differentiation is to think about what goes on in the body versus what goes on in the germ line, where imprinting is reset based on your gender.
The question, as Hasufin succintly put it:
This is called male-based inheritance. Most people think of the simple way to do this – it is a gene on the male-specific Y chromosome. But then point #1 will not be satisfied, as women can be X-men and they don’t have Y chromosomes.
The only way to explain this is imprinting. I differentiated between mutant and regular allele by calling them A versus a. I distinguished between paternally-inherited versus maternally-inherited mutant allele by A[sup]p[/sup] versus A[sup]m[/sup].
You can only be a mutant if you carry an A[sup]p[/sup]. Rogue, an X-man, is A[sup]p[/sup]a in all of the cells of her body except her gametes. In these, imprinting is reset and she generates A[sup]m[/sup] and a gametes, and therefore will not pass on X-manism to her children (provided she mates with a normal aa male.)
This gives rise to a whole set of possibilities (all of these assume normal mating to an aa individual). A[sup]p[/sup]a female mutants who never pass on their X-manism. A[sup]p[/sup]a male mutants who have 1 in 2 mutant children. A[sup]m[/sup]a normal males who now generate 1 in 2 mutant children. A[sup]m[/sup]a females who don’t have X-man children, but their sons can have X-man grandchildren.
I know this is confusing. This is one of the most confusing concepts in modern genetics around. When I too Human Genetics in grad school, this is what our final exam questions looked like.
biddee
Lady Chance was wrong, but not in a way that she or Johnathan Chance could have forseen. This type of inheritance has nothing to do with X or Y chromosomes. In this respect, Lady Chance was right – there is no way to explain this using traditional genetics.
Thank you, edwino, that makes sense. I remember imprinting from bio class and I understand now you were speaking of gametes.