scigirl

Here's a question for you, about some evidence for evolution of humans.

<a href="http://www.gate.net/~rwms/EvoEvidence.html" target="_blank">http://www.gate.net/~rwms/EvoEvidence.html</a>

Chimps have 24 chromosomes in their sperm/eggs, we only have 23. According to the site above, scientists speculated that perhaps two of the chromosomes fused in our chimp-like ancestor, giving us 23 chromosomes. If this theory is true, than we should see two things: two extra telomeres in our chromosome 2 (we have them), and an extra non-functioning centromere (we have it).

Keep in mind, the evolutionary tree (the one that says we share a common ancestor with chimps) was hypothesized by scientists before we had the genetic data (before we even knew what DNA looked like!)

The theory of evolution predicted that we should have the same, or nearly the same, chromosome number as chimps. We do.

Furthermore, the chromosome fusion theory predicts that we would find extra centromeres and telomeres. We did.

How does this evidence not support evolution? Do you have an alternate theory that explains this fusion evidence better? Let's hear it.

Here's a picture:



H = human (note there's only one), C = chimp, G = gorillla, O = orangutan. Note the three other primates have two chromosomes.

scigirl

Coragyps

Bump!

GeoTheo

I still don't see what the big deal is. It just points out that a fusion occured and that chimps and people once had the same number of chromosomes.

Vorkosigan

Geo, if they are not related, how is it that they had the same number of chromosomes? All of the great apes have 24 chromosomes, 'cept humans, which have 23. Like you said, the ancestor of humans once had 24 chromosomes....that's what it means.

KnightWhoSaysNi

Yes, but it's that common ancestry thing, as scigirl's post infers, that most creationists have a bone to pick with.

GeoTheo

We don't know what the effect of this fusion is on how these genes are expressed do We?
I mean if you could clone a human and put it back to how it's "supposed to be", Do you think the persons humerofemoral index will go up or somthing?

Coragyps

One of our real experts will correct me if I err, but I don't believe that that fusion event would have much of an effect on how the genes are expressed - just maybe that some alleles would be linked that were independent before. The chromosomes are just the carriers of the individual genes, so to speak. No single gene had to get mangled in that fusion.

scigirl

That is an interesting question.

However, the fact that we don't know is irrelevant.

All I'm saying with this post is . . . it's good evidence for common ancestry. That's it. I'm not trying to cure cancer or . . . drug addiction. . . here!

scigirl

[ July 24, 2002: Message edited by: scigirl ]</p>

KnightWhoSaysNi

With evidence like this, and with more evidence for common ancestry continuing to pour in as we learn more about genetics, I wouldn't be surprised if a new breed of anti-evolutionist appears. If it hasn't already happened in the 'intelligent design' movement, I'm predicting that the next generation's creationists will be the 'common ancestry creationists.'

They would concede that all life had a common ancestor, but would argue that God tinkered with the genetic process during speciation rather than natural selection, mutation, reproductive isolation, etc... Creationism will more and more creep its way to look like some form of theistic evolutionism.

[ July 24, 2002: Message edited by: Nightshade ]</p>

pseudobug

Hey Scigirl,

Do you happen to know if the gene arrangement in the vicinity of the fusion junction in the human chromosome is similar to that of chimp chromosome 24?

I'm too lazy and busy to go plowing through the literature to find out, but I would be willing to bet that many of the genes are ordered in the same manner.