Saturday, December 4, 2010

Human chromosome 2 and chimpanzee chromosomes 2p & 2q

A few years ago before I read The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution by Sean B. Carroll, before I read Why Evolution is True by Jerry Coyne, and before I read The Greatest Show on Earth, The Evidence for Evolution by Richard Dawkins, I read what biology professor Ken Miller said at the Dover trial.

When I read what Ken Miller said, I was shocked. I had already been studying evolution, off and on, for a few years, but somehow I never before heard of any evidence from molecular biology and genetics. After I got done reading Ken Miller's explanation of the prediction biologists had made about human chromosome two
I was totally amazed that scientific evidence could be so powerful. I thought, this is it, now creationists will finally understand how wrong they are. It turned out I was wrong, extremely wrong. I was wrong to think creationists had the ability to understand anything. I learned that evidence is completely meaningless to a creationist. I learned that creationists are creationists because they are the most fucking stupid subhumans who ever lived.

This information is in countless thousands of places on the internet. There are videos, diagrams, and explanations so numerous it would be impossible to find and study all of it in one lifetime. It's all extremely easy to understand, unless of course a person is a retarded creationist.

First my brief summary of this undeniable evidence for evolution, then I'm going to copy and paste what Ken Miller said about it (he also talks about it in videos, worth searching for if you have the time).

When the complete genome of both humans and chimpanzees became available for biologists to compare DNA sequences of these two
ape species, they noticed something very interesting. The human apes have 23 pairs of chromosomes, but the chimpanzee apes have 24 pairs. So biologists made two predictions. People must have a chromosome that is a fusion of two chromosomes, and there must be two chromosomes in chimps that match the fused chromosome in humans.

If these predictions turned out to be false, biologists would have to throw out 150 years of scientific progress and praise Jeebus.

Of course the predictions were correct, spectacularly correct, perfectly correct in every possible extreme detail. Evolution passed the test. We share an ancestor with chimps.

After the common ancestor of people and chimps split into two
lineages, one lineage developing into modern human apes, and the other lineage evolving into modern chimpanzee apes, one of our ancient ancestors was born with a fused chromosome. After several generations this fused chromosome spread throughout the small population of our ancestors and now the entire lineage had it. That's the only possible explanation, unless you're a fucking idiot who thinks a god fairy magically did all this stuff just to deceive thousands of scientists.

Here it is from Ken Miller, my copy and paste job from
Kitzmiller v. Dover Area School District
Trial transcript: Day 1 (September 26), AM Session, Part 2
:

Q. Could you give us another example?

A. Sure, I'm very happy to. The next slide, this is another test of the evolutionary hypothesis of common ancestry.

We have, as I'm sure most people know, 46 chromosomes
in our human cells. That means we have 23 pairs of chromosomes because you get 23 from mom and you get 23 from dad, so we've all got 46 total. We've got 23 pairs.

Now, the curious thing about the great apes is they have more. They have, as you can see from the slide, 48 chromosomes
, which means they have 24 pairs. Now, what that means, Mr. Walczak, is that you and I, in a sense, are missing a chromosome, we're missing a pair of chromosomes. And the question is, if evolution is right about this common ancestry idea, where did the chromosome go?

Now, there's no possibility that that common ancestry which would have had 48 chromosomes
because the other three species have 48, there's no possibility the chromosome could have just got lost or thrown away. A chromosome has so much genetic information on it that the loss of a whole chromosome would probably be fatal. So that's not a hypothesis.

Therefore, evolution makes a testable prediction, and that is, somewhere in the human
genome we've got to be able to find a human chromosome that actually shows the point at which two of these common ancestors were pasted together. We ought to be able to find a piece of Scotch tape holding together two chromosomes so that our 24 pairs -- one of them was pasted together to form just 23. And if we can't find that, then the hypothesis of common ancestry is wrong and evolution is mistaken.

Go to the next slide. Now, the prediction is even better than that. And the reason for that is chromosomes
themselves have little genetic markers in their middles and on their ends. They have DNA sequences, which I've highlighted in here, called telomeres that exist on the edges of the chromosomes.

Then they have special DNA sequences at the center called centromeres, which I've highlighted in red. Centromeres are really important because that's where the chromosomes
are separated when a cell divides. If you don't have a centromere, you're in really big trouble.

Now, if one of our chromosomes
, as evolution predicts, really was formed by the fusion of two chromosomes, what we should find is in that human chromosome, we should find those telomere sequences which belong at the ends, but we should find them in the middle. Sort of like the seam at which you've glued two things together, it should still be there.

And we should also find that there are two
centromeres, one of which has, perhaps, been inactivated in order to make it convenient to separate this when a cell divides. That's a prediction. And if we can't find it in our genome, then evolution is in trouble.

Next slide. Well, lo and behold, the answer is in Chromosome
Number 2. This is a paper that -- this is a facsimile of a paper that was published in the British journal Nature in 2004. It's a multi-authored paper. The first author is Hillier, and other authors are listed as et al. And it's entitled, The Generation and Annotation of the DNA Sequences of Human Chromosomes 2 and 4.

And what this paper shows very clearly is that all of the marks of the fusion of those chromosomes
predicted by common descent and evolution, all those marks are present on human Chromosome Number 2.

Would you advance the slide. And I put this up to remind the Court of what that prediction is. We should find telomeres at the fusion point of one of our chromosomes
, we should have an inactivated centromere and we should have another one that still works.

And you'll note -- this is some scientific jargon from the paper, but I will read part of it. Quote, Chromosome
2 is unique to the human lineage of evolution having emerged as a result of head-to-head fusion of two acrocentric chromosomes that remain separate in other primates. The precise fusion site has been located, the reference then says exactly there, where our analysis confirmed the presence of multiple telomere, subtelomeric duplications. So those are right there.

And then, secondly, during the formation of human chromosome
2, one of the two centromeres became inactivated, and the exact point of that inactivation is pointed out, and the chromosome that is inactivated in us -- excuse me, the centromere that is inactivated in us turns out to correspond to primate Chromosomes Number 13.

So the case is closed in a most beautiful way, and that is, the prediction of evolution of common ancestry is fulfilled by that lead-pipe evidence that you see here in terms of tying everything together, that our chromosome
formed by the fusion from our common ancestor is Chromosome Number 2. Evolution has made a testable prediction and has passed.

Q. So what you're testifying here is that modern genetics and molecular biology actually support evolutionary theory?

A. They support it in great detail. And the closer that we can get to looking at the details of the human
genome, the more powerful the evidence has become.


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Here's another copy and paste job about the same thing. It's also easy (for a normal person) to understand.

Everything you wanted to know about Chromosome 2 and evolution but were afraid to ask.

I recently joined Yahoo! Answers to give me something to do on my lunch breaks at work by answering peoples' questions about molecular biology and genetics (a niche that needed filling because it only took me a week to become a "Top Contributor" in biology). Yesterday, there was a challenge put towards "evolutionists" (ugh, how I hate that term): give the one (1) piece of evidence you would put forth to a creationist to try and sway his/her opinion on whether humans descended from earlier primates. There is literally a whole boatload of evidence to support man's descent from earlier primates, but picking the single piece of evidence to sway a creationist's opinion was tough. I thought about it for a minute and decided to present the case from Chromosome 2. I thought I'd reproduce my answer here:

You want one convincing proof? Consider this:

I'm sure you've heard that humans and chimpanzees have the vast majority of our DNA in common. You're also probably not convinced by this argument ("I don't understand...so what if two
organisms share the same genes? How does this prove that they came from the same lineage?"). But for now, forget about how very similar we are in our genetic sequence and let's focus on our chromosomes.

If you need a refresher, remember that the number of chromosomes
a species has tends to stay the same from generation to generation. A fruit fly has four autosomal chromosomes and one pair of sex chromosomes; it's offspring will all have the same number. What about us humans? We have 23 pairs of chromosomes; 46 chromosomes in total. If you took a karyotype - that's a display of all the chromosomes in a cell - of an ape (I know you're skeptical of humans being primates, but lets call 'em primates for now) you'll notice something different from human chromosomes: there's two extra! Apes have 48 chromosomes.

You might wonder how this proves we evolved from an ancestral primate. You might even suspect that it is evidence against such a claim, since an ancestral primate would have had 48 chromosomes
, and that number would have likely stayed constant down the generations, while in us, it's different. Well, this information alone does not prove much. But let's take a look at what the genome sequence shows us.

The sequence of the human
genome showed an interesting fact about our Chromosome 2. The area around the very centre of chromosome 2 (known as a centromere) looked an awful lot like telomeric DNA. Telomeres are the regions at the very ends of chromosomes; what were they doing in the centre of chromosome 2? Furthermore, each arm of Chromosome 2 had what appeared to be their own centromeres. Chromosome 2 was looking to be quite an oddity. No other human chromosome displayed these characteristics.

Once the chimpanzee
genome was sequenced, things got even more interesting. One of the chimpanzee's chromosomes was pretty much identical to the top half of the human chromosome 2. Another chimpanzee chromosome was nearly identical to the bottom half of Chromosome 2. On top of this, the banding pattern of these two chromosomes (as well as the same chromosomes in many other species of primates) was a complete match to the banding pattern of Chromosome 2.

Coincidence? Not likely. What this is, is evidence of a chromosomal fusion. An ancestral primate, ancestor to humans, chimpanzees and apes, had 24 pairs of chromosomes
. Eventually, this lineage diverged: apes and chimps went one way and we humans evolved along a separate path. But something interesting happened in the lineage that was to become humans: the two extra chromosomes from that ancestor fused together end to end to become human Chromosome 2. This is why our Chromosome 2 has what appears to be telomeres in its centre, and what appears to be two extra centromeres, one on each arm.

The only way to explain Chromosome
2's odd characteristics and similarity to other primates is with a chromosomal fusion. And the only way this could be possible is if we were descended from a common primate ancestor.

So, I put the question to you: if you could give only one single line of evidence for man's primate ancestry to change a creationist's mind, what would it be?


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This is one of the best videos about Human Chromosome Two
. It's a must-see video. Creationists, don't bother watching it because you're too fucking stupid to understand it.

Evidence of Common Ancestry: Human Chromosome 2

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In this video Ken Miller explains why Human Chromosome Two
is lead-pipe evidence for evolution. He said at the Dover trial, the anti-science creationists said nothing about Human Chromosome Two after Ken Miller and another witness explained it. The creationists didn't want to talk about it.

"The intelligent design advocates had literally nothing to say (about Human Chromosome Two)"

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Professional Liars For Jeebus spread lies about this evidence, but they can't answer this question.

"
Now, the question has to be asked - if the similarities of the chromosomes are due only to common design rather than common ancestry, why are the remnants of a telomere and centromere (that should never have existed) found at exactly the positions predicted by a naturalistic fusion of the chimp ancestor chromosomes 2p and 2q?"

Comparison of the Human and Great Ape Chromosomes as Evidence for Common Ancestry

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The existence of Human Chromosome Two
is by itself more than enough to call evolution a proven scientific fact. But evolution deniers need to understand that this is just one of countless thousands of equally powerful evidences for evolution. If a creationist wanted to spread lies about all the evidence for evolution, he would have to be lying non-stop for the rest of his life, which by the way is what the stupid assholes of the anti-science Christian Creationist Discovery Institute do for a living.

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