Freethought & Rationalism Archive

Blinn · 09-07-2002, 07:52 PM

Quote:

Originally posted by Vanderzyden:
No one, I say no one, has posted anything of substance regarding a demonstration of fusion.

Vanderzyden

Well, Mageth posted <a href="http://www.faseb.org/genetics/ashg99/f2062.htm" target="_blank">this</a> which you then referred to as a supposed fusion. How is it that two chromosomes that are not fused in the parents yet are fused in the offspring are �supposed�?

Here�s a full paper, <a href="http://www.uiowa.edu/~molbio/JournalPDF/cellBioII/Hemann.pdf" target="_blank">The Shortest Telomere, Not Average Telomere Length, Is Critical for Cell Viability and Chromosome Stability</a> where end-to-end chromosome fusions were studied. Unless you assert that the authors are lying, I believe you have to concede that chromosome fusions do happen. Please don�t call these �supposed.� Hopefully you�ll be able to download this document. I wasn�t able to view pages 7 and 10.

Here are the important parts relative to your claim that telomere-to-telomere fusions don�t happen. Please don�t try to shift the goalposts either.

Quote:

To understand the role of telomeres in chromosome maintenance in normal and in cancer cells, we generated telomerase null mice mTR_/_ (Blasco et al., 1997). In the absence of telomerase, telomere shortening is not balanced by elongation. The first mouse generation lacking telomerase is designated mTR_/_ G1, and sub-sequent generations derived through interbreeding are designated mTR_/_G2 through mTR_/_G6. mTR_/_ G1 mice show no phenotype, as only a small amount of (TTAGGG)n telomere repeat is lost from chromosome ends in this first generation. With each successive generation of interbreeding, telomeres become shorter, and in the later generation (mTR_/_ G4-G6) mice, chromosome end-to-end fusions are seen in lymphocytes and embryonic fibroblasts (Blasco et al., 1997; Lee et al., 1998).

Other mechanisms that cause telomere dysfunction can lead to chromosome fusion.

Quote:

The generation of chromosome end-to-end fusions in late generation mTR_/_mice indicates that progressive shortening results in the loss of telomere function. Different mechanisms that cause telomere dysfunction result in similar cellular consequences (Hemann et al., 2001a). Expression of a dominant negative TRF2 a mammalian telomere binding protein, results in chromosome fusion, cell cycle arrest and p53-dependent apoptosis (Karlseder et al., 1999). Likewise, telomere shortening in mouse results in chromosome fusion, cell cycle arrest, and p53-dependent apoptosis (Blasco et al., 1997; Chin et al., 1999; Lee et al., 1998). Mutations in Taz1, a telomere binding protein in S. pombe, result in chromosome fusion and fertility defects (Cooper et al., 1998; Nimmoet al., 1998), phenotypes that are prominent in late generation mTR_/_mice. Finally, alterations in telomere repeats by introduction of mutant telomerase RNA in yeast and mammalian cells also result in chromosome fusion and cell cycle arrest(Guiducci et al., 2001; Kim et al., 2001; Kirk et al., 1997; Marusic et al., 1997; McEachern and Blackburn, 1995). In all of these cases, including telomere shortening, loss of specific proteins at telomeres likely leads to the recognition of chromosome ends as DNA breaks.

<a href="http://www.uiowa.edu/~molbio/JournalPDF/cellBioII/Hemann.pdf" target="_blank">The Shortest Telomere, Not Average Telomere Length, Is Critical for Cell Viability and Chromosome Stability</a>

edited for lots of paste errors.

[ September 07, 2002: Message edited by: Zetek ]

Valentine Pontifex · 09-08-2002, 06:49 AM

Quote:

Originally posted by Zetek:

Here�s a full paper, <a href="http://www.uiowa.edu/~molbio/JournalPDF/cellBioII/Hemann.pdf" target="_blank">The Shortest Telomere, Not Average Telomere Length, Is Critical for Cell Viability and Chromosome Stability</a> where end-to-end chromosome fusions were studied. Unless you assert that the authors are lying, I believe you have to concede that chromosome fusions do happen. Please don�t call these �supposed.� Hopefully you�ll be able to download this document. I wasn�t able to view pages 7 and 10.

I could not see pages 7 or 10 either, nor Figure 2. For the missing two pages Acrobat is reporting two few operands. Thus the coding of the PDF is faulty. Acrobat is also reporting a code it does not recognize. Considering that I just upgraded to the latest release, this should not have happened.

===

For the pages that are not missing, the take home lesson is clear though. Observations of fussions are quite common. Heck they cite Barbara McClintock's work on them in the 1940s as well as reporting the many fussions which they observed. And even show, via experimental results that chromosomes with telomeres are more likely to undergo fussion. Vander and you still in this thread? You have been shown to have been wrong.

Lizard · 09-08-2002, 09:06 AM

I'm going to go way out on a limb here and make a prediction:

We will not hear from VZ again.

Jesus Tap-Dancin' Christ · 09-08-2002, 09:10 AM

Quote:

Originally posted by Lizard:
I'm going to go way out on a limb here and make a prediction:

We will not hear from VZ again.

Just like Eternal?

Bet he still denies their existence.

scigirl · 09-08-2002, 12:29 PM

Quote:

Originally posted by Lizard:
Questioning orthodox interpretations is not a bad thing. It's done all the time in the sciences. It's how scientists make their name -- by altering or extending the usefulness of a theory: witness Gould and Eldredge. It's also what keeps science dynamic and relevant.

Thoughtful scientists add much to the store of knowledge by questioning what everyone else accepts. However, what VZ is doing is something different. Here, someone who admits to being uneducated in the matter at hand is questioning things which are so well-supported by either direct observation or extensive testing over decades that to question their validity is absurd.

Lizard, thank you for putting into words what's been in my mind. My sentiments exactly.

scigirl

Starboy · 09-08-2002, 12:47 PM

It would have been wonderful if Vanderzyden's denial of existing evidence could be backed up with some good science supporting his claims. Without new evidence all he can produce is a great deal of heat and noise with no light. That may be permissable in philosophy, but it is quickly dismissed in science.

Starboy

Baloo · 09-13-2002, 08:06 AM

Quote:

Originally posted by Mageth:
I posted that abstract several pages ago, Zetec. If it wasn't read and understood the first time, I doubt if it will be this time.

Quote:

Originally posted by Vanderzyden:

The reason I didn't pay much attention is that it's yet another example of a supposed fusion in the context of a tragic abnormality.
Please tell me where I can find the entire paper. "Program Nr: 2062" isn't very helpful. Google searches for the authors and the laboratory only produce the link to which you are pointing.

(Link for full paper given)

Quote:

Originally posted by Vanderzyden:

I'm curious: How did you find the reference? Do you have the full paper?

Thanks,

Vanderzyden

(Method for finding paper given)

Quote:

Originally posted by Vanderzyden:
(utter silence)

Anywone else here wondering if Vanderzyden just hoped this thread would go away?

Blinn · 09-13-2002, 10:59 AM

He was shown to wrong, so what else can he do but change the subject?

Blinn · 09-14-2002, 04:38 PM

*bump*

Hey Vander, I'm assuming from your silence on the issue, that you would prefer to ignore the fact that you have been shown to be wrong. Would you like to continue to deny the fact of chromosome fusion, or should we just end this thread?

[ September 14, 2002: Message edited by: Zetek ]

Doubting Didymus · 09-22-2002, 06:45 PM

As the most recent incarnation of the vanderzyden all-purpose thread has been moved to misc disc, where it is more on topic, I am dredging this one back up, as the actual science topics like phylogeny, fusion, and genetic homology still need to be settled.

My own pet topic with vander at the moment is the level of agreement between phylogenetic trees. I will repeat my question for vander here:

Vander, you request references that demonstrate the level of agreement in phylogenetic trees. I have several times now offered a simple quote to that effect from a current university approved biology textbook. Will that be sufficient, and if not, what more do you need?

09-14-2002, 04:38 PM	#289
Blinn Veteran Member Join Date: Aug 2001 Location: Ohio, USA Posts: 1,162	bump Hey Vander, I'm assuming from your silence on the issue, that you would prefer to ignore the fact that you have been shown to be wrong. Would you like to continue to deny the fact of chromosome fusion, or should we just end this thread? [ September 14, 2002: Message edited by: Zetek ]</p>

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09-08-2002, 09:06 AM	#283
Lizard Regular Member Join Date: Apr 2001 Location: Kansas Posts: 169	I'm going to go way out on a limb here and make a prediction: We will not hear from VZ again.

09-08-2002, 12:47 PM	#286
Starboy Banned Join Date: Jun 2002 Location: Tallahassee, FL Reality Adventurer Posts: 5,276	It would have been wonderful if Vanderzyden's denial of existing evidence could be backed up with some good science supporting his claims. Without new evidence all he can produce is a great deal of heat and noise with no light. That may be permissable in philosophy, but it is quickly dismissed in science. Starboy

09-13-2002, 10:59 AM	#288
Blinn Veteran Member Join Date: Aug 2001 Location: Ohio, USA Posts: 1,162	He was shown to wrong, so what else can he do but change the subject?

09-22-2002, 06:45 PM	#290
Doubting Didymus Veteran Member Join Date: Jul 2002 Location: East Coast. Australia. Posts: 5,455	As the most recent incarnation of the vanderzyden all-purpose thread has been moved to misc disc, where it is more on topic, I am dredging this one back up, as the actual science topics like phylogeny, fusion, and genetic homology still need to be settled. My own pet topic with vander at the moment is the level of agreement between phylogenetic trees. I will repeat my question for vander here: Vander, you request references that demonstrate the level of agreement in phylogenetic trees. I have several times now offered a simple quote to that effect from a current university approved biology textbook. Will that be sufficient, and if not, what more do you need?

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