NationStates Jolt Archive

EDIT: I was right, Alien Born confirmed this in post 4. Please do not post saying this is impossible. Do continue discussing it, however.


Well, not really evils so much as something that has been bugging me for a bit...

I was wondering about genetics the other day, as I often do for no apparent reason, when I began wondering about chromozones and reproduction. If a human being is created out of pairs of chromozones, half a pair from each parent, then isn't it possible that a brother and a sister could share no similar genetic information at all?

Aside from the genes that all humans share in common, what if the pairs of chromozones for one child were the opposites of the ones of the other child? Let's pretend humans only have three chromozone pairs. The chromozones of a mother are (A1A2-B1B2-X1X2). The chromozones of the father are (A3A4-B3B4-X3Y1). Therefore, two possible children are (A1A3-B1B3-X1X3) and (A2A4-B2B4-X2Y1). These siblings have no common genetics! Is this possible, or am I being stupid?

Well, not really evils so much as something that has been bugging me for a bit...

I was wondering about genetics the other day, as I often do for no apparent reason, when I began wondering about chromozones and reproduction. If a human being is created out of pairs of chromozones, half a pair from each parent, then isn't it possible that a brother and a sister could share no similar genetic information at all?

Yes, but extremely unlikely*. That would make them a clone of one parent, I think!


Imagine the genes are Dad: (ABC) Mum: (DEF)

The chance of getting A instead of D is 0.5 (or B instead of E, C instead of F)
So the chance of ABC instead of DEF is 0.5 * 0.5 * 0.5 = 0.125

But humans don't have three genes, we have millions, so thats a very small probability indeed.

All the variables make by brain hurt...

Yes it is possible that even non monozygotic twins could share absolutely no genetic material. There is a section in Heinlein's "Time enough for love" concerning this.

No it would not make either of them clones, they would simply be ordinary offspring. The chances are extremely low of it hapening spontaneously.

That the children share no genes, does not mean that they do not share genetic parents. Their genes came from the same people. What it would mean is that there would be no genetic reason to prohibit breeding between the pair. There would still be cultural and social reasons though.

These siblings have no common genetics! Is this possible, or am I being stupid?

I would say it is not possible for two reasons. The first being that there are recessive and dominate genes. So both siblings will likely have the dominate genes in common.
Second the parents will have genes in common even if they are not related at all.
As Humans all of us have over 90% (98% I THINK) of our D.N.A. in common.

Yes, but extremely unlikely*. That would make them a clone of one parent, I think!


Imagine the genes are Dad: (ABC) Mum: (DEF)

The chance of getting A instead of D is 0.5 (or B instead of E, C instead of F)
So the chance of ABC instead of DEF is 0.5 * 0.5 * 0.5 = 0.125

But humans don't have three genes, we have millions, so thats a very small probability indeed.

No, you misunderstand... The way you've put it, it's as if chromosomes don't exist!

Each parent is a group of genes called chromosomes, you know that, I should hope... There's 46 in all, but 23 pairs of the same data... So "packets" of millions of genes are sent at once. The child wouldn't be a clone, that's impossible. The chance of what I am describing is ((1/2)^46)^2, I think... Still unlikely, but not how you put it at all.

I would say it is not possible for two reasons. The first being that there are recessive and dominate genes. So both siblings will likely have the dominate genes in common.
Second the parents will have genes in common even if they are not related at all.
As Humans all of us have over 90% (98% I THINK) of our D.N.A. in common.

You'll notice I said EXCEPT those 98% that all humans share at the top... In bold, actually.

Yes it is possible that even non monozygotic twins could share absolutely no genetic material. There is a section in Heinlein's "Time enough for love" concerning this.

No it would not make either of them clones, they would simply be ordinary offspring. The chances are extremely low of it hapening spontaneously.

That the children share no genes, does not mean that they do not share genetic parents. Their genes came from the same people. What it would mean is that there would be no genetic reason to prohibit breeding between the pair. There would still be cultural and social reasons though.

Yes, this is the point I was trying to make! Thank you for making it clearer.

No, you misunderstand... The way you've put it, it's as if chromosomes don't exist!

Each parent is a group of genes called chromosomes, you know that, I should hope... There's 46 in all, but 23 pairs of the same data... So "packets" of millions of genes are sent at once. The child wouldn't be a clone, that's impossible. The chance of what I am describing is ((1/2)^46)^2, I think... Still unlikely, but not how you put it at all.

So, what your saying is that each chromosome just contains millions of different versions of a gene for the same thing? Wouldn't that mean that a human body could be described by only 23 variables?

If not, and each of the million genes does something different, then aren't I correct?

So, what your saying is that each chromosome just contains millions of different versions of a gene for the same thing? Wouldn't that mean that a human body could be described by only 23 variables?

If not, and each of the million genes does something different, then aren't I correct?

No. First of all, each gene only creates one type of molecule. That's all it does. Secondly, chromosomes are bundles of genes. There are 46 chromosomes. Two of each type. So yes, half of your genetics do the same thing as the other half. The entire human body is 23 chromosomes. This is basic genetics, I'm not going to explain it to you. When a sperm meets an egg, it's not as if all 3 billion genes are mixing up. Read about DNA and chromosomes on Wikipedia.

So, what your saying is that each chromosome just contains millions of different versions of a gene for the same thing? Wouldn't that mean that a human body could be described by only 23 variables?

If not, and each of the million genes does something different, then aren't I correct?

No. Each chromosome contains several genes that do different things. Some genes are included on multiple chromosomes, and there are several different variations of each gene that could appear on a given chromosome. A gene is essentially a LONG combination of four "letters", or nitrogen-based molecules. Every three letters is code for one amino acid. Changing even one letter can have very adverse affects. Thus, the variables in the human body are really the amino acids that code for proteins, the amount of these proteins produced, the rate at which they're produced, when they're produced, etc.

oh how i love evil empires, they make wonderful jam. :sniper: :gundge:

oh how i love evil empires, they make wonderful jam. :sniper: :gundge:

It's true, you know.

No, you misunderstand... The way you've put it, it's as if chromosomes don't exist!

Each parent is a group of genes called chromosomes, you know that, I should hope... There's 46 in all, but 23 pairs of the same data... So "packets" of millions of genes are sent at once. The child wouldn't be a clone, that's impossible. The chance of what I am describing is ((1/2)^46)^2, I think... Still unlikely, but not how you put it at all.
You're forgetting crossing over, which becomes extremely common the farther apart from each other the genes are. It's nearly 100% for genes loci that are on opposite sides of the genomes.

You're forgetting crossing over, which becomes extremely common the farther apart from each other the genes are. It's nearly 100% for genes loci that are on opposite sides of the genomes.

True, but irrelevant. The scenario I described is possible. I was just trying to explain genetics to Shadowstorm in as few words as possible, since he seems to have a very loose grasp on the subject.

True, but irrelevant. The scenario I described is possible. I was just trying to explain genetics to Shadowstorm in as few words as possible, since he seems to have a very loose grasp on the subject.
But crossing over makes you scenario so unlikely that the probability of it happening is efffectively null.

But crossing over makes you scenario so unlikely that the probability of it happening is efffectively null.

That still doesn't matter. This is a hypothetical situation and I wanted to know if it was possible. No matter how unlikely something is, there is still a chance it will happen unless it is impossible. It's always good to know the difference between impossible and improbable.