I recently came across a page giving evidence for fusion in human chromosome 2 -- it was the first time I had heard about this. The conclusion of the article is:
The evidence that human chromosome 2 is a fusion of two of the common ancestor's chromosomes is overwhelming.
I searched the web in vain for any creationist response to this--I only found some creationist skepticism about whether there really were telomene structures in the middle of the human chromosome (which seems unjustified), and large numbers of evolutionists doing victory dances. So I was forced to actually think about it myself (oww, painful!), taking it on trust for now that the facts presented on the site linked above are basically correct. The process was quite helpful to me, and perhaps might be useful to other people, so here goes. I'm mainly looking at this from an explicitly creationist perspective, but some of this may apply to some intelligent design positions.
The problem with the conclusion, and with much of the discussion, is that it mingles the evidence with the explanation--so the conclusion, as stated, assumes that there was a common ancestor between apes and humans, which makes it difficult to use it as evidence for a common ancestor. To untangle this, let's rewrite the conclusion so that it no longer makes this assumption:
The evidence that human chromosome 2 is the fusion of two chromosomes is overwhelming. The two chromosomes it appears to derive from are directly analgous to chromosomes that are found in apes.
However, once you make this change, an explanation that agrees with creationist accounts of human ancestry just falls out. It would go something like this:
Humans were created in a separate creative event from the other primates, but with 24 chromosome pairs just like them. At some point early in human history, fusion of the chromosomes occurred to give us the 23 pairs we have now. All living humans are descended from those in which the fusion occurred.
The point is simply this: the evidence points to the fusion of human chromosomes, but gives no indication when this happened, except that it must have occurred to a creature that was the ancestor of all living humans. Since none of the apes share this fused chromosome, there is no reason at all to date this fusion any further back than warranted, so it becomes unnecessary to even posit the existence of a common ancestor between apes and humans based on this evidence alone.
What is interesting is this: at first glance, looking from an evolutionary perspective, this seems to have dealt a death blow to creationist accounts of human origins. (The main problem for the creationist is why God would have chosen to create humans with chromosomes that have useless bits in them i.e. the telomene sequences in the middle, and in a way that mimics fusion of 2 chromosomes).
But actually, the evolutionary interpretation has overstepped the mark -- it doesn't demonstrate common ancestry, it assumes it. All the way through it talks about the chromosomes of a common ancester etc. But by putting the evidence into the evolutionary framework ahead of time it has confused what the evidence actually points to. The evidence does indicate (assuming that the God-created-it-to-look-like-fusion explanation is invalid) that human chromosomes were once more similar to those of apes than they are currently, but that is all.
The article also states:
Not only is this strong evidence for a fusion event, but it is also strong evidence for common ancestry; in fact, it is hard to explain by any other mechanism.
The main basis for saying this appears to be the statement: "At the place where we would expect it on the human chromosome we find the remnants of the chimp 2q centromere". But of course, as the author explains later, we don't actually find the chimp 2q centromere -- there is no label on it saying "I'm a chimp 2q centromere". What we find is the remnants of centromere that is in the same place, relative to certain sequences, as the 2q centromere is in chimps. All this shows is that the ancestor chromosomes (i.e. before the fusion event) of current human chromosomes were closely analagous to chromosomes of apes, including chimps.
So the author claims we can rule out other accounts of human origins, but is unjustified in doing so. The reason for this logical mistake is that he/she has intertwined the evidence and the evolutionary explanation so tightly, and seen that they fit so well, that the author cannot imagine another explanation would fit. In reality, the evidence fits a creationist explanation equally well--there is nothing contrived or tricky about what I have presented, and if evolutionary theory did not exist, there is nothing in this evidence that would make creationists think of common descent. The idea that humans originally had a complete set of chromosomes that correspond to ape chromosomes, rather than only 23 out of 24, does not shake creationist ideas one little bit. We already knew there was a vast amount of similarity between humans and primates both in terms of physical characteristics and genetic material and structure. It is a mistake of the evolutionary mindest to assume that observing similarities necessarily brings you to the conclusion of common descent. Taxonomy based on physical characteristics was already a very well established science when the idea of common descent came on the scene, and people from both the intelligent design and the creationists camps have no problem in understanding physical and genetic similarities that are not rooted in common descent -- that is, it is easy to think of perfectly adequate reasons why a designer (either an unknown intelligence in the case of ID, or God in the case of creationism) might have reused designs.
A lesson for both sides to take away is the importance of detaching yourself from your current position in order to see where the evidence actually points. It is easy to imagine that because evidence fits with your position, and fits very well, it therefore not only confirms your position but disconfirms the rival theories.
[Note, I realise that I'm likely to get flamed for this entry, as I have been in the past for the smallest references to things of this nature. Since this is my blog, and I'm interested in intelligent debate, and don't want my readers to have to trall through screens of rubbish, I will not hesitate to delete comments that are just stupid and contribute nothing. I promise not to censor you if you have something intelligent to say, and I am genuinely interested in any flaws in my logic or gaps in my knowledge of the evidence.]
Comments §
http://www.ideacenter.org/contentmgr/showdetails.php/id/1392
Obviously one item like the chromosome 2 fusion doesn't stand alone but is just one peice of a larger puzzle. You may find this interesting (http://talkorigins.org/faqs/comdesc/) as an example of a more thorough case for common descent. I've been working through it but it is long and detailed, but I'd be interested if you find any major problems with his reasoning.
And as always, it's easy enough to fire shots at an opposing theory, it's much more convincing if you can show evidence for your theory rather than evidence against the opposing theory.
Second, with regards to that response, although I readily admit that Luskin shows ignorance in some areas. However, the fundamental argument he makes (the same as I the one I make here) is not at all refuted, and Luskin is right to point out that Darwinists have taken the evidence further than it actually points.
It is true that Darwinism would have predicted this fusion event. But this is not, by itself, evidence for Darwinism *over and against* intelligent design. As pointed out in this article on Bayesian statistics (http://www.yudkowsky.net/bayes/bayes.html), when analysing how much some evidence confirms a theory you need to take into account the fact that *other* theories may fit with your evidence equally well. For example, very often evidence that seems to confirm Newtonian equations of motion cannot be used *against* Einsteinian versions, because very often they predict the same thing (within experimental error).
Third, creationism/ID *are* capable of making predictions. One example, off the top of my head, is that animals/plants, since they are created to reproduce "according to their kinds" according to Genesis, will be observed to be limited in the amount of variation that is possible naturally. This is observed in our experience, and from what we can see in the fossil record (which demonstrates a huge amount of *stasis*, not change, and leaves very little room for any evolution). The very fact that creationism could conceivable be disconfirmed (e.g. by fossil or other evidence for common descent) demonstrates that creationism is indeed testable. You cannot say that creationist/ID theories are both demonstrably false (which most Darwinists do) and unfalsifiable.
- Can you think of any possible observation that would be out of sync with the creationist hypothesis? I can't, which is why I believe saying that something doesn't disagree with the creationist hypothesis is not very informative. It's really easy to think of things that could be out of sync with the evolutionary hypothesis (e.g. fish going through a hair covered mammal like stage as part of their development cycle would be at the very least hard to fit into a darwinian framework).
- Evidence for common decent (of which there is plenty in the article above) would not dis-confirm creationism. It would merely show the mechanism for creation.
- I guess I'm not won over by the "according to their kinds" argument. It does however fit the hypothesis that a bunch of farmers a couple thousand of years ago who believed in god saw that sheep make sheep and cows make cows and then they wrote this observation down. Kind of a vacuous prediction. Also this prediction is not out of sync with an evolutionary process that occurs over millions of years.
- junk dna
I'm not an authority but I did work in bioinformatics for a couple of years studying retroid agents (a variety of what is sometime called "junk dna") in the human genome.
There are several classes of junk dna - pure junk, simple replicators and retroid agents/retroid viruses.
Of these three, retroid agents have been found to have some functions both harmful and helpful to humans. Simple replicators have no known function they just copy themselves around, sort of like a benign computer virus. And pure junk is just junk as far as anyone knows. While some scientists may have jumped the gun on some of their predictions that all "junk dna" has no purpose, there certainly is vast quantities of random noise in our genome. Who knows what the future will bring but it is incorrect to say that there is not a large quantity of content in our genome that is still classified as random junk with no known purpose. It's actually quite easy to download the entire genome (it's only 3 Gb) and look at it visually. Its surprisingly easy to pick out some of the junk sections by eye. Also there are a number of genome browsers available on the web. It's quite stunning to see the vast expanses of unused space in our dna.
- vestigial organs
I'm not familiar with your list of 100s of mispredicted vestigial organs do you have a pointer? At best evolution predicts that vestigial organs are a possibility. If some scientists mistakenly interpret some as vestigial it doesn't invalidate that possibility. And I guess I want to be sure what you are implying. Are you saying that creationism predicts there is no such thing as a vestigial organ on any species anywhere (and no such thing as "junk dna")?
If creation and evolution are defined more narrowly then they can both be disconfirmed, though neither can be disconfirmed easily with some blank/white test. Most creationists would reject the idea that humans and apes share a common ancestor, and since it is possible to find evidence for common descent here, strong enough evidence would demonstrate them to be wrong. Creationists don't buy into "God could have done it that way to trick us" arguments (not any longer, anyway). You are right to imply that such evidence wouldn't convince them that God doesn't exist, but I make no apology for that.
Creationism also obviously includes ID theory, which can also be disconfirmed scientifically. See:
http://www.ideacenter.org/contentmgr/showdetails.php/id/1156
(The bottom of that page also has information about functions found for DNA sequences that were previously thought to be junk)
Vestigial organs: I've read the figure '180' often used for the number of supposed vestigial human organs in 1890. For evidence of 86 of these, see http://en.wikipedia.org/wiki/Robert_Wiedersheim
W.R.T. junk DNA/vestigial organs, you are right that IDers/creationists wouldn't rule out the possibility of these. But it is interesting that the basic assumption of 'useful' has generally proved more helpful to biology than the assumption of 'useless'.
http://www.ideacenter.org/contentmgr/showdetails.php/id/846
So all organisms (including humans) that appear to modern science to have vestigial organs are all hoaxes or poor science? And all junk DNA will turn out to be useful? Do I have that right?
I guess the most amazing thing is that while the majority of biologists embrace evolution as the most powerful guiding principle in their field a computer guy such as your self is able to to see through the obvious veil of lies. With no formal training even! [OK, that ends my brief slide into sarcasm.]
I look forward to continuing our previous email conversation when you have the time.
Anyway, it's best to continue this by email, as you say.
[feel free to delete this comment - not sure how else to contact you]
Anyway, thanks for your explanation. The youtube video I watched of this did make me think, but you made me rethink.
If a god did create us, then with the fact of chromosome 2, it just shows that god is a deceiving god. So the fusion of the two chromosomes supports either evolution or a deceiving god.
Also, that is *all* I was saying, not saying that I have an answer for every puzzle of biology. With respect to the fossil record, the implicit suggestion is that the fossil record obviously supports evolution. Those who have the smallest knowledge about what many top *evolutionists* say will know that in many places the fossil record is extremely puzzling to the theory of evolution, and ultimately does not provide evidence for it -- it is *interpreted in the light of* evolution.
This argument is qualitatively and quantitatively wrong.
Qualitative difference: While the evolutionary argument is conclusive, the creationist argument leads to other questions, such as: Why did god create us with 48 chromosomes, although apparently, we are doing just fine with 46? Therefore, it does not explain the observation, just accommodates it.
Quantitative difference: Evolutionary argument restricts the space of possible observations much more tightly than the creationist argument does. And the observations happen to obey those restrictions. Therefore, the observations are much more statistically significant for the evolutionary argument, providing much stronger statistical support. Here is what I mean:
- If your hypothesis is that humans, chimps, gorillas, and orangutans have a common ancestor and the closest relatives to each other, then (i) you expect very close chromosome numbers and relatively few chromosome duplication/fusion events in each species and (ii) you expect the observed duplication/fusion events to be coincide with the differences in the genomes of these species. In the "chromosome 2" case, these hold. There is only one recent fusion event, and this happens to underly the difference (in chromosome numbers) between humans and the other three ape species. What a divine coincidence!
- If your hypotheses is that all these species were created independently and then underwent chromosomal rearrangements in themselves, then (i) the chromosome numbers can be much more diverse, and (ii) there is no reason for the observed duplication/fusion events be consistent with other species. But they are.
Besides all these, this beautiful piece of evidence is not the only evidence for common ancestry between humans and other apes; it is just one of many (e.g., non-functional similarities like those in the psi-beta-1 pseudogene) that fits to the solution of the puzzle very nicely.
So, my dear friend, your creativity is appreciated, but unfortunately refuting the obvious requires much more effort. Good luck!
Well done sir.
I believe Luskin accepts that the fusion arose from within the human lineage.
Does the chromosome thus come with labels attached saying that it arose from a fusion of two other human chromosomes?
If not, then Luskin cannot really say anything, can he? And neither can you!
Your "labels" argument undercuts any thing one may say about any evidence for anything. Thus, if no label comes with X, then no theory about X can be provided because the evidence only makes it look that way.
For example, the earth does not really orbit the sun. The evidence we have only makes it look that way. We would know for sure if the earth had a label attached saying that it was orbiting the sun. But since that label does not exist, then geocentricism is just as valid as heliocentricism.
Would you accept this argument? If so then your use of "labels" is consistent. If not, then you use it in a very self serving manner.
Because those chromosomes sure look like fused ape chromosomes and not fused human ones, then what is your bet that it is the fusion of two ape chromosomes that arose in the human lineage after the human/ape split?
(And because the evidence makes it look as if the earth really does orbit the sun, then what is your bet there, too - that it is just as likely that the sun orbits the earth?)
Regards, Roland
The difficulty with the alternative hypothesis is explaining the correspondence between the DNA sequences. Specifically, the banding pattern (and at a lower level, the underlying gene A-C-G-T sequences causing them) of chromosome 2 corresponds to a fusion (complete with telomere segment) of chimpanzee genes 2p and 2q, within the expected mutation level for the ~6 My since the split.
The difficulty with the creationist explanation is it assumes God was directly involved in generating the roughly 400 megabits of similarity, without specific evidence to support a claim that he had to be. This is mathematically unjustifiable. (For the high-level math basis, see papers "Minimum Message Length and Kolmogorov Complexity", by C. S. Wallace and D. L. Dowe; "Minimum Description Length Induction, Bayesianism and Kolmogorov Complexity", by Paul M. B. Vitanyi and Ming Li. They basically boil down to a rigorous and provable form of Occam's Razor.)
While it may be "easy to think of perfectly adequate reasons why a designer [...] might have reused designs", without extensive evidence to back whatever reason given, it becomes an unsupported assumption that reduces the relative probability (Vitanyi-Li paper, again) to nearly nil when compared to the standard explanation.
Oh, and speaking of mathematics and evolution, the just-out paper "Prevolutionary dynamics and the origin of evolution" (Nowak and Ohtsuki in PNAS) not only shows how the miscalculations of the probability of life constantly bandied by "cdesign proponentsists" of all flavors are wrong, but shows how selection for replication precedes and leads to replication itself... and in turn, life.
A fusion like this would occur in a very small and most likely isolated population, so that trait would only be common to one group most likely. This would mean that the majority of humans would have 48 chromosomes with a very small proportion have 46. It is completely implausible to think that there was a fusion in EVERY single human being at the same time. If what you say is true, then some humans would have 46 while the vast majority would have 48.
@abb3w: Mainly your comments were insults, I was tempted to delete. The main thing you add is the mutation rate thing, but creationists have very different models of mutation rates and their causes. Finally, you talk some nonsense about needing to prove what I state about a designer -- essentially you are trying to build an argument that makes "a designer did it" always an invalid explanation. But you will have noticed in real life (and archaeology etc) that "a designer did it" is often a valid and correct conclusion, even when we don't know the identity/psychology of the designer.
Your opening argument is that human/ape chromosome argument is flawed because the argument assumes common ancestry. But this is the basis of the scientific method. Create a hypothesis that explains what you know, develop predictions based on this hypothesis and then verify the predictions. If you go through this cycle many, many times your hypothesis may get elevated to the status of a theory. But make a false prediction and your theory is out the window.
I have a theory of my own that states that nothing makes sense, everything is random and that we are at the front of an incredible series of coincidences. Tomorrow, time may start to go backwards, I will fall through the earth and atoms will become galaxies ... My theory is irrefutable, explains everything and predicts nothing.
I note that Paul and MK both try to equate faith in science and faith in God as equal approaches to understanding. Paul says that you cannot prove anything to be absolutely true. I think this severely misrepresents science. For something to become a theory in science requires a tremendous amount of evidence supporting it. When Einstein developed his theory of General Relativity, they really did have to travel to the far ends of the earth to verify it. And it was only after the observation of the anomalous perihelion of Mercury that his hypothesis was given credence. It further predicted the Cosmic Background Radiation and is now used millions of times a day to adjust the clocks in your GPS system. You may also propose that the earth really is at the center of the universe and that the plants and the sun are moved around by spirits and that God just makes the distant stars look like they are very far away.
How do you distinguish between these two world views. They both explain everything that we observe. The latter theory even has the power to explain things that scientists can yet explain. What came before the big bang - there wasn't one, God just made it look that way, why is there no anti-matter in the universe - God made it that way, what is Dark Matter - don't know, but God made it that way.
So why do most people, even die hard creationists accept Einstein's view of the Cosmos versus the earth centric view. One reason is that Einstein's view (and in its simpler form, Newtonian Mechanics) makes verifiable predictions of things we can observe - planetary orbits, bouncing billiard balls, flying airplanes, rockets etc. Another reason is that it is the simplest explanation (Occam's razor). With a few equations and some pretty brutal mathematics it can explain the drop of a sparrow and the creation of stars. You may call this a faith in science, but this faith is supported by observations going out to 20 significant digits. I don't see an equivalent basis for the faith in God.
Now the theory of evolution is not as easily testable as General Relativity. It does not predict a specific event that you can measure in a laboratory. However, it does make predictions. Which is what brought me to this site. If apes and man are supposedly descended from a common ancestor, why do we only have 23 chromosomes and they have 24? From and evolutionary standpoint, the apes could have duplicated a chromosome, or one of theirs could have split into two, or two of the human chromosomes could have fused. Now when you look at human chromosome 2, it looks a lot like the combination of chromosomes 2p and 2q in apes. OK, that is a pretty good data point. Is there anything else? It also looks like there was a fragment of chromosome 1 transferred to the Y chromosomes in the common ancestor of humans, chimpanzees and bonobo, but not in gorillas.
So under evolutionary theory, the common ancestor of humans, chimpanzees and bonobos broke off from the great apes with the transposition of a fragment of chromosome 1 to the Y chromosome, then humans broke away from the chimpanzees and bonobos with the fusion of chromosome 2p and 2q - random genetic mistakes over time. What is the creationist's explanation for this? God created the apes with 24 chromosomes and the chimpanzees and bonobos with 24 chromosomes but moved a piece of chromosome 1 to the Y chromosome and created humans with chromosomes similar to the chimpanzees but chromosomes 2p and 2q later fused together. The creationist explanation looks a little like spirits pushing planets around the heavens. But evolution predicts more. If humans are closer to chimps than apes, there should be other markers that confirm this. How do the mitochondria in humans compare to chimps and apes. They should be closer to chimps. A quick check of the internet and I found '... the mtDNA ... data favor a closer relation of chimpanzees and humans than gorillas and humans.' (http://www3.interscience.wiley.com/journal/110531975/abstract?CRETRY=1&SRETRY=0)
So, from a prediction standpoint, evolution does pretty well. If they had found a completely different chromosome 2 from apes that would have been pretty damning for evolution. Or if human mitochondria were closer to gorillas than chimps, how would it explain the transposition of chromosome 1 DNA. God of course could pick and choose how to make humans, so this would favor creationism - but it didn't.
But what is the actual theory of creation from the point of view of creationism and ID? Did man walk fully formed unrelated to other animals? Was there just one man and one woman? Who did their children mate with? When did this happen? Is this consistent with the genetic variability of the humans we observe today?
Second, while the YEC have different models for mutation, the formal description under their models increases Message Length Induction immensely, indicating incorrectness.
Third, yes, design is sometimes a correct explanation. However, design is itself an evolutionary process; see Basalla's "The Evolution of Technology" (ISBN 0521296811). It's only the element of purpose which distinguishes design. While we need not know the identity of the designer, we must infer the existence of a designer, and of a purpose for the design before we can infer that something was designed. Without additional evidence to justify those premises separately, design again increases Message Length Induction and indicates incorrectness.
I read your piece and have two comments (questioning the logic) to make.
1) I do see you point about evolutionists assuming an ape ancestor, but I dont see the relevance. Obviously science "assumes" evolution. A scientist makes an "asumption" (a hypothesis), observes/looks for evidence to confirm/deny this assumption, and makes predictions based on it. If the hypothesis is "evolution", and the observation is 46 instead of 48 chromosomes, seemingly contradicting the hypothesis, then the logical "prediction" to explain this has to be something like "a fusion of chromosomes happened", for which evidence is then looked for and, in this case, found. Doesnt "prove" evolution, but it does put another feather in its hat, another piece of the jigsaw puzzle that "fits", making evolution an even more "likely" explanation of the world around us.
Second, you say "Humans were created in a separate creative event from the other primates, but with 24 chromosome pairs just like them. At some point early in human history, fusion of the chromosomes occurred to give us the 23 pairs we have now. All living humans are descended from those in which the fusion occurred."
If you accept that a fusion of chromosomes actually happened, isnt this fusion still a sign of "change" from "old human" to "new human"? If we were originally designed with 48 chromosomes, why the need for this fusion? How did it happen? Why? Was there a "design fault" in the old human that needed tweaking? Why is the "old human" no longer here? Why did it disappear? Did it die out? Was it "unfit for use", and became extinct? Or just "erased" from earth? Also, more importantly, isnt this "tweak", a modification, actually an example of "evolution"? If you accept the fusion happened, then the real question has to by "what made it happen?" - lucky fluke mutation and environmental pressure, or act of a designer unhappy with his original design?
The problem with your interpretation is that it is strickly ad hoc.
Scientific theories must be falsifiable, primarily through making testable predictions. Given the difference in chromosome number between apes and humans, evolutionary theory predicts that there must have been a joining of two chromosomes. If a search of chromosomes had revealed no such joining, that would have shown that the theory of evolution is false, at least so far as a common ancestor of ape and human is concerned. The fact that a joining was found provides substantial evidence in support of evolution.
On the other hand, there is nothing in creationism that, on noting the simple fact of the difference in chromosome number, would require a prediction (emphasizing "prediction") concerning a joining of two chromosomes before the finding of such. In other words, evolution necessarily predicted that such a joining would be found. Your interpretation, on the other hand, was made post finding, or ad hoc. Before the finding, there would have no reason or basis for making such a prediction from the creationist standpoint. You felt it necessary to make the interpretation only after the finding was made. In fact, it seems to me that I remember reading a long time ago a creationist argument that humans and apes could not be related because of the difference in chromosome number. I doubt that back then a creationist would have made a "prediction" that a joining of the two chromosomes would be found.
That is the problem with creationism. Any "predictions" or explanations that its followers make are strictly ad hoc. They are attempts to make the facts fit the creation model rather than to learn where the truth is. That also gets into the bigger question of the reliability of the Bible. In my research, I have found that there is no reason to believe that the Bible is the word of God.
A correction to my last post. I said that evolution necessarily predicted that such a [chromosomal] joining would be found. I meant to say that evolutionary theory necessarily predicted that such a joining would be found.
The evolutionary process itself did not require a joining of the chromosomes. Such a joining would have been purely random, and could as well have to not occurred as well as to have occurred. But once it occurred, it was subject to natural selection. If it was detrimental, it would have been selected against by natural selection and would likely have disappeared in the human lineage. That it was retained means that it was either neutral or, more likely, beneficial (probably because the bringing of certain genes in closer proximity resulted in a beneficial characteristic).
That underscores the difference between the evolutionary process and evolutionary theory. What happened during the evolutionary process restrains evolutionary theory. The different number of chromosomes in ape and human requires an explanation by evolutionary theory. Evolutionary theory makes a prediction about this, as I pointed out in my last post, and that prediction has been verified, thus providing evidence for the validity of the theory of evolution.
Again, your interpretation concerning the finding about the joining of the chromosomes was strictly ad hoc. Your interpretation that God originally created humans with 48 chromosomes was made only because of the finding. Before that finding was made, there would have been no basis from the creationist standpoint for making a prediction that the two chromosomes would be found to have been joined.
Therefore, regardless of evolution, it should have been a no-brainer to see similarities in humans and apes without the assumption that evolution is greater (or lesser) than intelligent design.
Anyway, I don't know if you already know about this, but I came across this interesting article:
http://mbe.oxfordjournals.org/cgi/content/full/24/3/853
It compares human and chimpanzee Y-chromosome, and it finds that (among others) a particular gene (USP9Y) that is present in a human Y-chromosome is not functional in a chimpanzee's Y-chromosome. It appears (from an evolutionists perspective) that a gene that was present in the common ancestor of humans and chimps was damaged somewhere in the chimpanzee lineage. However, in humans, this gene is crucial for the production of sperm cells, and disruption of this gene results in male infertility.
If in our hypothetical common ancestor, this gene had a similar function and was thus important for reproduction, how can the chimp's ancestor have lost it? The author of the article writes that "the potential loss of this specific gene in the chimpanzee lineage is especially puzzling."
Given the fact that chimpanzees nowadays are perfectly fertile, I must assume that they have another gene (or genes) that provides the function USP9Y has in humans. These genes must have been present before the loss of the USP9Y-gene in the chimpanzee lineage, or otherwise this loss could not have survived in their genome. But if USP9Y was still functional, how could the alternative mechanism have evolved while there was no need for it?
If you have two lines that aren't parallel (i.e. closer at some points than at others) it makes more sense to think that they intersect at some point than they simply appear (particularly in this metaphor because we've never seen species appear out of nowhere). This alone is by no means definitive but add piles of other similarities between our two 'lines' and common ancestry makes way more sense.
[q] At some point early in human history, fusion of the chromosomes occurred to give us the 23 pairs we have now. All living humans are descended from those in which the fusion occurred. [/q]
would form an intermediate belief. Seeing that the Logos (Christ) became flesh, and is known as the 'last Adam', it would stand to reason that they would both share the 'same flesh' as it were. In fact, that's not just doctrine, but dogma. If 'God created man in His image', the original 48ers would qualify, but not those of us who remain. If the fusion (as seems to be suggested) took place prior to Christ, He is not a true 'Man' as God created in His own image. It would be a quandry then, that God Himself would not *actually* be made in His own image. I've yet to come across a Creationist (I HATE the phrase 'Intelligent Design') argument that really comes close to starting to deal with this.
BTW, if you are studying theology at a secular University I'm not at all surprised at your current crisis, it is not at all uncommon. Studying theology from those least qualified to teach it (due to wicked hearts that want to surpress the truth) is asking for trouble, IMHO. Most theology courses are designed specifically to destroy belief in God. At the very least, you have to go in to them with the attitude that you are completely prepared to believe that the lecturers and scholars are outright liars. "Let God be true and every man a liar". It really isn't far from the truth - the amount of nonsense that comes from so called scholars in this department is astonishing.
Please feel free to e-mail me about any of these things, I'd love to hear from you.
Should we find many more "creatures" like us if Evolution is REAL?
Good article, however, I do have to point out in the interest of fairness. Even though I agree with you that the conclusion in the original paper may present a biased representation of common descent (albeit slight, it is instead based on previous science), your rewording of it ("Humans were created in a separate creative event from the other primates, but with 24 chromosome pairs just like them. At some point early in human history, fusion of the chromosomes occurred to give us the 23 pairs we have now. All living humans are descended from those in which the fusion occurred.") is also biased in that it presupposes that man was created. I don't particularly agree with your perspective, but I do respect the way you're arguing it.