Human chromossomes
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CH2O2

Portugal

#1 Jul 9, 2013
Humans have 1 less pair of chromossomes than the other great apes because of a fusion between 2 chromossomes.
Now, please dont kill me already but I have a question. And I don't have any hidden agenda. Really!
I consider it is logical that there was a first human (or human ancestor) who suffered this chromossome fusion.(Oh boy, this is starting to sound bad... I'm going to get murdered) If this is the case, how did this first human reproduce with other humans with a different number of chromossomes. How would meiosis produce compatible eggs and sperm between humans with a different number of chromossomes?

I'm sure there is an explanation. After all we are here. Does anyone know how?

“I can never convince the ”

Level 9

Since: Jan 11

stupid that they are stupid.

#2 Jul 9, 2013
CH2O2 wrote:
Humans have 1 less pair of chromossomes than the other great apes because of a fusion between 2 chromossomes.
Now, please dont kill me already but I have a question. And I don't have any hidden agenda. Really!
I consider it is logical that there was a first human (or human ancestor) who suffered this chromossome fusion.(Oh boy, this is starting to sound bad... I'm going to get murdered) If this is the case, how did this first human reproduce with other humans with a different number of chromossomes. How would meiosis produce compatible eggs and sperm between humans with a different number of chromossomes?
I'm sure there is an explanation. After all we are here. Does anyone know how?
I'll give you the benefit of the doubt. Even if you have a hidden agenda, it germane to my answer. I will say if you don't have an agenda, you seem to protest a bit much, but perhaps that is just being gun shy.

The fusion of the two chromosomes occurred after our ancestors split from chimpanzees. Chromosome fusions are not unknown to science and occur in other animals. This fusion of the chromosomes does not mean there was a loss of genes. It just means the total number of chromosomes is reduced from the ancestral number. As long as their are no related inhibiting factors, mitosis and meiosis would be able to proceed as normal. The number of chromosomes would just be less. As far as breeding is concerned, they probably mated like normal since there shouldn't have been any change in phenotype and besides guys always say their phenotype is six inches long regardless. Since we don't have evidence of the success of reproduction between individuals with the ancestral and derived karyotype, I don't have an answer for that. However, the genomic and molecular evidence shows that our chromosome 2 is a fusion of the ancestral chromosomes 13 and 14 (I may not be remembering the correct chromosomes, but it doesn't change the fact of the fusion) that are still retained as individual chromosomes in the other hominoids. So we cam infer that some matings must have been successful until the reduced karyotype was fixed in the population. Presumably the fused condition conferred a benefit that allowed it thrive or it was fixed due to drift.

So based on my limited knowledge, we have the fact of the fusion of that is human chromosome 2 corroborated by several lines of evidence and my speculation of possibilities of this condition becoming fixed in the ancestral population. Others will correct me, fill in gaps or communicate this better, but I thought I would give it a start.

Level 9

Since: Sep 08

Everett, WA

#3 Jul 9, 2013
Even today you can see breeding between species that have different number of chromosomes. The horse world is full of them. zebras can breed with donkeys and donkeys can have up to 20 more chromosomes than zebras.

http://en.wikipedia.org/wiki/Zebroid

When the fusion first occurred in our line it probably put up no barriers to breeding at all.

“Maccullochella macquariensis”

Since: May 08

Melbourne, Australia

#4 Jul 10, 2013
The thing to understand is that the underlying DNA is essentially the same between the organism with the fused chromosome and the one without. It may not even have required an advantage from the change for it to have "stuck". In other words the mutation might not be selected through the normal natural selection process, it might simply be an artefact of chemistry. Perhaps when a fused organism breeds with a non-fused the result is fused progeny in all or most cases simply for chemical reasons to do with the DNA molecule itself.

“I can never convince the ”

Level 9

Since: Jan 11

stupid that they are stupid.

#5 Jul 10, 2013
Bluenose wrote:
The thing to understand is that the underlying DNA is essentially the same between the organism with the fused chromosome and the one without. It may not even have required an advantage from the change for it to have "stuck". In other words the mutation might not be selected through the normal natural selection process, it might simply be an artefact of chemistry. Perhaps when a fused organism breeds with a non-fused the result is fused progeny in all or most cases simply for chemical reasons to do with the DNA molecule itself.
I wondered about that when I cast my speculation above.

Level 2

Since: Jul 13

Lisbon, Portugal

#6 Jul 11, 2013
But how does a viable fertilized egg form from eggs and sperm with different number chromossomes. I know it happens with closely related species, like the ones in subduction zone's example. My question is more about the celular mechanism involved at fertilization.

“The Thunder Rolls”

Since: Jul 13

The Lightning Strikes

#7 Jul 11, 2013
In DNA repair a cell identifies and corrects damage to the DNA molecules that encode its genome. If it can't be repaired it sometimes goes into apoptosis. What is the science hypothesis of how repair or apoptosis was learned by the cells?

“Maccullochella macquariensis”

Since: May 08

Melbourne, Australia

#8 Jul 11, 2013
CH2O2 wrote:
But how does a viable fertilized egg form from eggs and sperm with different number chromossomes. I know it happens with closely related species, like the ones in subduction zone's example. My question is more about the celular mechanism involved at fertilization.
Chromosomes are just a way that the DNA molecules are physically organised, it's still the same inside. Just after a fusion event the rest of the DNA is still the same, not counting the usual number of point mutations that occur with every fertilisation - I think the number is about a hundred or so for humans. There are no problems with interbreeding due to chromosome fusion, the whole argument is a non-starter.

I might add that you are not doing your stated case for being a non-creationist any good here. We have seen plenty of creationists do exactly the same - you appear to have dropped the idiotic kind thing and now you have shifted onto chromosome fusion as your cause célèbre. This is a tactic we see all the time. It looks like you are using a shopping list of so-called problems taken from a creationist web site.

You need to understand that every one of these so-called problems has been thoroughly de-bunked any number of times. The makers of those web sites know that their readers will not check out any of their claims. They also do not understand that science does not work on the basis of authority. The opinions of a great scientists are not listened to because of his or her position, but because their work has been checked and confirmed by many others and found to be valid. The more this is dine the more their opinion is valued, but even the most well regarded scientist's opinion is only as good as it correlates with the evidence. Fundies on the other hand are all about authority, their positions are true in their mind because of who says things or is alleged to have said things, no checking of evidence allowed.

All you are doing is demonstrating your complete lack of understanding about the subject. If you were genuinely looking for information you would not be asking anonymous members on an Internet forum, you would go and look at some actual scientific web sites (or maybe even - shock, horror - a book) that explain this in much greater detail than anyone here is likely to, with the possible exception of members like Katydid or Darwin's Stepchild. However, it is not their job in any case to educate you, the responsibility for that is yours alone. Hey, maybe you could even enrol in a course at a reputable university if you really want to know this stuff.

The significant thing you are doing that gives the game away is that you continue to argue nonsense after your questions have been answered. If you were genuinely seeking information you might ask further questions seeking clarification of a particular point but you adopt an argumentative style. This sets off my fundy radar. Right now it is pinging like hell.
The Dude

Birkenhead, UK

#9 Jul 12, 2013
Hidden Blitz wrote:
In DNA repair a cell identifies and corrects damage to the DNA molecules that encode its genome. If it can't be repaired it sometimes goes into apoptosis. What is the science hypothesis of how repair or apoptosis was learned by the cells?
That's like asking how did water learn to freeze or magma learn how to form rocks.

“The Thunder Rolls”

Since: Jul 13

The Lightning Strikes

#10 Jul 12, 2013
The Dude wrote:
<quoted text>
That's like asking how did water learn to freeze or magma learn how to form rocks.
Water didn't learn to freeze, when it gets cold it freeze's because molecular movement is slowed enough that the molecules stick to each other and form ice crystals.

Magma didn't learn to make rocks, once molten magma erupts from the volcano it becomes lava and as it starts to cool (normal temp is around 750° C. but can go as high as 1,250° C.) it hardens and solids are formed.

But then again magma/lava and water are not living things so your argument is moot.
Gillette

Fairfield, IA

#11 Jul 12, 2013
Hidden Blitz wrote:
<quoted text>
But then again magma/lava and water are not living things so your argument is moot.
Not moot at all. Tell us why we should not assume and look for an equally natural set of principles and laws that govern how DNA repairs itself and propagates, itself, etc.?

Why in the world would we need to posit that there is a bearded, white-robed, enthroned Middle Eastern "God" standing behind each phenomenon, pulling the strings and making everything work?

Where is the evidence of that? ANY evidence? Any need to resort to that kind of deus ex machina?

While we DO have evidence of natural causes and contributing factors.

“I can never convince the ”

Level 9

Since: Jan 11

stupid that they are stupid.

#12 Jul 12, 2013
Hidden Blitz wrote:
<quoted text>
Water didn't learn to freeze, when it gets cold it freeze's because molecular movement is slowed enough that the molecules stick to each other and form ice crystals.
Magma didn't learn to make rocks, once molten magma erupts from the volcano it becomes lava and as it starts to cool (normal temp is around 750° C. but can go as high as 1,250° C.) it hardens and solids are formed.
But then again magma/lava and water are not living things so your argument is moot.
I'm not well versed in physics, but doesn't water freeze because molecular movement slows and the molecules arrange themselves in a lattice structure to form crystals? I think magma cooling to rock follows the same process.

“I can never convince the ”

Level 9

Since: Jan 11

stupid that they are stupid.

#13 Jul 12, 2013
Hidden Blitz wrote:
In DNA repair a cell identifies and corrects damage to the DNA molecules that encode its genome. If it can't be repaired it sometimes goes into apoptosis. What is the science hypothesis of how repair or apoptosis was learned by the cells?
I don't know the current hypotheses for either of these phenomena, but there is a lot of research being done on them. Perhaps a Google search might be a better place for you to look.

However, learned may not be the proper context to frame your question. Learn in the context of cell and molecular biology is a metaphor and as such is imperfect as a complete and proper description.

“The Thunder Rolls”

Since: Jul 13

The Lightning Strikes

#14 Jul 12, 2013
DanFromSmithville wrote:
<quoted text>I'm not well versed in physics, but doesn't water freeze because molecular movement slows and the molecules arrange themselves in a lattice structure to form crystals? I think magma cooling to rock follows the same process.
Well if you want to get technical most liquids freeze by crystallization, formation of crystalline solid from the uniform liquid. This is a first-order thermodynamic phase transition, which means that, as long as solid and liquid coexist, the equilibrium temperature of the system remains constant and equal to the melting point. Crystallization consists of two major events, nucleation and crystal growth. Nucleation is the step wherein the molecules start to gather into clusters, on the nanometer scale, arranging in a defined and periodic manner that defines the crystal structure. The crystal growth is the subsequent growth of the nuclei that succeed in achieving the critical cluster size.
I just gave a short version that anyone could understand. I see now that here a person had better dot their I's and cross their T's or it will be thrown against them.
The Dude

Birkenhead, UK

#15 Jul 12, 2013
Hidden Blitz wrote:
<quoted text>
Water didn't learn to freeze, when it gets cold it freeze's because molecular movement is slowed enough that the molecules stick to each other and form ice crystals.
Magma didn't learn to make rocks, once molten magma erupts from the volcano it becomes lava and as it starts to cool (normal temp is around 750° C. but can go as high as 1,250° C.) it hardens and solids are formed.
But then again magma/lava and water are not living things so your argument is moot.
Then I guess trees had to learn to grow tall and seeds and leaves obviously, because they are living things. Although last time I checked they didn't have any kind of learning capacity.

“The Thunder Rolls”

Since: Jul 13

The Lightning Strikes

#16 Jul 12, 2013
The Dude wrote:
<quoted text>
Then I guess trees had to learn to grow tall and seeds and leaves obviously, because they are living things. Although last time I checked they didn't have any kind of learning capacity.
Typical answer. When you don't have an answer you project out dogma bull.

Level 9

Since: Sep 08

Everett, WA

#17 Jul 12, 2013
Hidden Blitz wrote:
<quoted text>
Typical answer. When you don't have an answer you project out dogma bull.
No, he is pointing out that your use of the word "learning" is incorrect.
The Dude

Birkenhead, UK

#18 Jul 12, 2013
Hidden Blitz wrote:
<quoted text>
Typical answer. When you don't have an answer you project out dogma bull.
Don't blame me for following your analogies and showing them to be flawed.

Level 2

Since: Jul 13

Lisbon, Portugal

#19 Jul 12, 2013
Bluenose wrote:
<quoted text>
Chromosomes are just a way that the DNA molecules are physically organised, it's still the same inside. Just after a fusion event the rest of the DNA is still the same, not counting the usual number of point mutations that occur with every fertilisation - I think the number is about a hundred or so for humans. There are no problems with interbreeding due to chromosome fusion, the whole argument is a non-starter.
I might add that you are not doing your stated case for being a non-creationist any good here. We have seen plenty of creationists do exactly the same - you appear to have dropped the idiotic kind thing and now you have shifted onto chromosome fusion as your cause célèbre. This is a tactic we see all the time. It looks like you are using a shopping list of so-called problems taken from a creationist web site.
You need to understand that every one of these so-called problems has been thoroughly de-bunked any number of times. The makers of those web sites know that their readers will not check out any of their claims. They also do not understand that science does not work on the basis of authority. The opinions of a great scientists are not listened to because of his or her position, but because their work has been checked and confirmed by many others and found to be valid. The more this is dine the more their opinion is valued, but even the most well regarded scientist's opinion is only as good as it correlates with the evidence. Fundies on the other hand are all about authority, their positions are true in their mind because of who says things or is alleged to have said things, no checking of evidence allowed.
All you are doing is demonstrating your complete lack of understanding about the subject. If you were genuinely looking for information you would not be asking anonymous members on an Internet forum, you would go and look at some actual scientific web sites (or maybe even - shock, horror - a book) that explain this in much greater detail than anyone here is likely to, with the possible exception of members like Katydid or Darwin's Stepchild. However, it is not their job in any case to educate you, the responsibility for that is yours alone. Hey, maybe you could even enrol in a course at a reputable university if you really want to know this stuff.
The significant thing you are doing that gives the game away is that you continue to argue nonsense after your questions have been answered. If you were genuinely seeking information you might ask further questions seeking clarification of a particular point but you adopt an argumentative style. This sets off my fundy radar. Right now it is pinging like hell.
Basically, what you are saying is that if I have a question I should not bother asking it in a forum dedicated to that subject and insted go read a book. Or maybe what you are saying is that you just don't like me and this forum should be off limits for me. Give me a break, will ya?
Gillette

Fairfield, IA

#20 Jul 12, 2013
CH2O2 wrote:
<quoted text>
Basically, what you are saying is that if I have a question I should not bother asking it in a forum dedicated to that subject and insted go read a book. Or maybe what you are saying is that you just don't like me and this forum should be off limits for me. Give me a break, will ya?
No, he's saying that you have all the earmarks of a fundamentalist Christian Creationist or IDer PRETENDING to be pro-science, then slipping little anti-science doubts in there.

We've seen it a thousand times and no one will be surprised when you start laying out Bible quotes, etc. LOL!

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