Traces of Evolution in Chromosome 2

[Xaero]

A little late but here is the first of my threads i want to share with you ...


Looking at chromosome 2 in the human genome one can find the remnants of a fusion of 2 chromosomes:
two centromeres and telomeres in the center, which are normally found at the ends of chromosomes.

The telomere sequence is highly conserved in different groups of organisms. For example vertebrates have the sequence TTAGGG repeated many times. (In primates the sequence is repeated 500 to 3500 times). Adjacent to the telomere, are regions with other DNA repeats (known as Telomere Associated Repeats) but these regions, rather than being highly conserved, are highly polymorphic - that is they have many variations even within the same species. Nevertheless the pretelomeric region can be easily recognised in closely related species. Occasionally genes are found in the pretelomeric region.

Now these telomeric and pretelomeric sequences are normally found only on chromosome ends. However, in human chromosome 2, there is strong evidence for chromosome fusing in that there is a pretelomeric sequence, a telomeric sequence, an inverted telomeric sequence and an inverted pretelomeric sequence in that order in the middle of the chromosome.

One centromer is inactive and it can be shown that this is the centromer of chromosome 2q which you can find in gorillas and chimps.

Its centromere is at the same place as the chimpanzee chromosome 2p as determined by sequence similarity. Even more telling is the fact that on the 2q arm of the human chromosome 2 is the unmistakable remains of the original chromosome centromere of the common ancestor of human and chimp 2q chromosome, at the same position as the chimp 2q centromere (this structure in humans no longer acts as a centromere for chromosome 2.

http://www.evolutionpages.com/chromosome_2.htm


Now the theological question regarding creationism is why did god create these clear signs of chromosome fusion ex nihilo?

 

[laptoppop]

Similarity in structure can be used to support similarity in history or similarity in designer. God used the same set of "building blocks" and engineering tradeoffs in much of His design.

 

[Assyrian]

So, Special creation, or redesigned Chimp?

 

[random_guy]

Similarity in structure can be used to support similarity in history or similarity in designer. God used the same set of "building blocks" and engineering tradeoffs in much of His design.

So every similarity is explained as common design. Every difference is creative design. It's the answer for everything and explains nothing. You still haven't explained why there's telemeres found in the chromosome, when, normally, they only occur at the end of a chromosome. Kind of funny how in humans, they're in the chromosome. Explained (and predicted ) by evolution, ad hoc away by Creationists.

 

[Mallon]

So every similarity is explained as common design. Every difference is creative design. It's the answer for everything and explains nothing.

Indeed.
Apparently God gave birds and insects different solutions to the problem of flying because He was feeling creative that day.
Was He therefore feeling lazy when He gave all tetrapods the same limb elements for getting around?

 

[laptoppop]

Actually similar design and structure reuse is a prediction for a created (engineered) item as well.

My point is that whether you believe in a quick 6 day creation, or a millions of years God-guided development, you'd expect to see elements of design, and we do. They aren't evidence one way or the other for the two models. Now if you go to atheistic evolution, you might expect to see more random development - but that's a different forum.

 

[random_guy]

Actually similar design and structure reuse is a prediction for a created (engineered) item as well.

My point is that whether you believe in a quick 6 day creation, or a millions of years God-guided development, you'd expect to see elements of design, and we do. They aren't evidence one way or the other for the two models. Now if you go to atheistic evolution, you might expect to see more random development - but that's a different forum.

Nitpick, it's not atheistic evolution or theistic evolution, it's just evolution. Evolution is not atheistic any more than gravity, geology, or chemistry is atheistic.

Not random development, but reusing existing structures for new purposes. For example, the panda's thumb is nothing more than a modified wristbone. Evolution explains this. Creationism explains this as creative design. Good luck doing any science when the answer to why something is such and such is, "God did it". It's as ad hoc as you can get. Creationist will never be able to explain why God choose to be creative one day then use similar design the next day.

 

[Xaero]

For what reason would the designer put an inactive centromer into chromosome 2 that looks like the rest of chromosome 2q found in chimpanzee and gorilla?

Also the sequences around the telomeres look similar without any functional reason.
It serves only for teaching us about our origins.

 

[random_guy]

Using information from another thread, to refute the common/creative design argument,, how does Creationism explain the many different forms of antifreeze protein? Evolution explains it as convergent evolution, and molecular and genetic evidence supports the theory that the protein was evolved independently in several different groups.

The antifreeze protein is that several groups of fish that have the protein split apart around 40 million years, but the fishes all have some form of the protein. According to evolution, the genetic sequences should show differences since the gene wasn't around before the split. Research shows that this theory is probably correct.

Parallelism in the case of AFGPs is quite nicely borne out in the second paper (2), in which Chen et al. describe the sequence of the AFGP gene from the Arctic cod, Boreogadus saida, and compare it to the notothenioid Dissostichus AFGP gene. Arctic cod and notothenioid AFGPs are nearly identical in amino acid composition and are comprised mainly of Thr-Ala-Ala repeats. In fact it was with a notothenioid gene probe (to the AFGP repeats) that Chen et al. isolated the Arctic cod gene, but the organization and sequence of the genes bespeaks their separate ancestries (Fig. 1). First, the coding regions flanking the AFGP repeats in the Arctic cod (including the signal peptide region) are not at all similar to notothenioid AFGP nor trypsinogen; indeed these regions in the Arctic cod AFGP are not identifiably similar to any known sequence. Second, the gene structure of the Arctic cod is quite different from the notothenioid AFGP, with each having different numbers and locations of introns, for example, in differing positions within the signal peptide. Since intron positions are highly conserved in vertebrate genes, they are reliable indicators of homology. Third, the repeating Thr-Ala-Ala of the AFGPs appears to be of different genetic origins. In the notothenioid, there is a strong bias for the specific codons aca-gct/g-gca, whereas many of the Arctic cod repeats are not this sequence, but instead use codons rarely if ever observed in the notothenioid AFGP gene. Finally, the spacers (which provide sites of posttranslational proteolytic cleavage) between AFGP repeats are clearly unrelated (having no sequence similarity) and are presumably processed by different proteases. Given all of this, Chen et al. (2) make a very strong case for the independent origins of AFGP genes.

So all Creationism can say is common design mixed with creative design. Evolution provides solid evidence that suggests that the protein evolved independently in different groups and provides lots of evidence to support the claim.

 

[laptoppop]

Or there is a purpose we are not yet aware of.

 

[Xaero]

Why didn't god designed chromosome 2 like any other chromosome, with just one centromer?

Creationists should give an honest and detailed answer why there are remnants of fusion inside chromosome 2.
This simple evidence alone tears down every attempt to attack evolution using genetics

 

[random_guy]

Why didn't god designed chromosome 2 like any other chromosome, with just one centromer?

Creationists should give an honest and detailed answer why there are remnants of fusion inside chromosome 2.
This simple evidence alone tears down every attempt to attack evolution using genetics

It's not just that it has 2 centromer, but the DNA sequences line up with 2p and 2q in chimp chromosomes. It's extremely hard for Creationists to account for that. That's why the only answer they have is, "Cuz Goddidit that way." Any other explanation would not stand up to scientific scrutiny.

 

[Xaero]

It's not just that it has 2 centromer, but the DNA sequences line up with 2p and 2q in chimp chromosomes.

That's right but creationists would argue that these structures have functions and are only common design. But nonfunctional remnants are something that is even more worse for ID&creationism.

 

[random_guy]

That's right but creationists would argue that these structures have functions and are only common design. But nonfunctional remnants are something that is even more worse for ID&creationism.

To be fair, we don't know if they are truly non-functional or not. There may be something very weird that goes on. That said, what's most bizarre is why God seems to do everything to point towards chromosome fusion and common ancestory, then laugh and say, "That's what you get for using your brains. It was specially created this way to trick every single scientist!"

 

[laptoppop]

2 points.
First, I am always careful when someone says "no use" or "no function" because so many times in the past it has been discovered that things we thought were of no use turned out to have use.

Second, even if they are unused, it poses no problem for ID or creationism. Design does not equate to perfection. When God finished he said it was "good" not that it was perfect. In our current system there are tons of different tradeoffs that have been made. Man could run faster, but if he did there would be other issues.

Yes, this may seem like handwaving "God did it" -- but the point is that this type of "evidence" really does nothing for or against creationism OR evolution.

 

[random_guy]

2 points.
First, I am always careful when someone says "no use" or "no function" because so many times in the past it has been discovered that things we thought were of no use turned out to have use.

Second, even if they are unused, it poses no problem for ID or creationism. Design does not equate to perfection. When God finished he said it was "good" not that it was perfect. In our current system there are tons of different tradeoffs that have been made. Man could run faster, but if he did there would be other issues.

Yes, this may seem like handwaving "God did it" -- but the point is that this type of "evidence" really does nothing for or against creationism OR evolution.

I can conceed it may not be for or against creationism because anything can be handwaved away as "Goddidit." However, how can this not be evidence for evolution? Evolution theorizes that human and modern chimps share a common ancestor. We find out that chimps have 24 chromosome pairs and humans have 23 chromosome pairs. This suggests that either chimps went through chromosome fission or humans when through chromosome fussion. When we finally had the ability to sequence chromosomes, we find that evidence points towards chromosome fusion, since we find the ends of chromosomes in the middle of human chromosome 2.

I would love to see how you justify this as not supporting evolution.

 

[Xaero]

Design does not equate to perfection.

But why did the design look like fusion? There are telomeres inside the chromosome which could normally only be found at the ends of chromosomes?

 

[Xaero]

There is also a good video explaining this topic: http://www.youtube.com/watch?v=Gs1zeWWIm5M

 

[Deamiter]

It's interesting how you (laptoppop) insist on directly observed evolutionary changes (and only on those large enough to have taken millions of years by mutation and selection) and refuse to consider that all these similarities are indirect evidence for evolution.

I mean, if it were all due to a common designer, wouldn't you expect to find common designs that did not fit into a nested hierarchy? I mean shouldn't just ONCE an organism far down the reptilian lines share a feature with something far down a mammilian line that isn't shared by any of their common ancestors?

I mean I know to you common ancestors are all made up, but if this happened even once (and if this design hypothesis were true, I'd expect it MUCH more than once!) it would disprove current evolutionary theory. Even in convergent evolution (where two animals in seperate lines develop similar structures like bats, insects and birds) there is no genetic crossover that's unique to the organisms with that structure.

Evolution predicts that a mammal (births young, has mammary glands etc...) will never have genes related to insect or bird flight and that mammal wings will be a modification of other mammal parts. This chimera connection is never found.

ID might predict that similar structures would be the result of similar genes... but that's not seen. Not ONCE has the nested hierarchy been broken. That doesn't seem promising for a hypothesis that claims each 'kind' was created totally seperate of each other.

I can't emphasize this enough -- a nested hierarchy is predicted and is required by evolution. It is neither predicted nor required by special creation. So why has it never once been broken?

 

[laptoppop]

Yes, this can be seen as a support for evolution. Beautiful repetitive and creative design can also be seen as a support for creationism.

Bottom line - 1-1 tie. Not in "favor" of one or the other.