FRDB Archives

Freethought & Rationalism Archive

The archives are read only.


Go Back   FRDB Archives > Archives > IIDB ARCHIVE: 200X-2003, PD 2007 > IIDB Philosophical Forums (PRIOR TO JUN-2003)
Welcome, Peter Kirby.
You last visited: Yesterday at 05:55 AM

 
 
Thread Tools Search this Thread
Old 09-05-2002, 12:02 PM   #211
Regular Member
 
Join Date: Jun 2000
Location: St. Louis, MO
Posts: 417
Post

Quote:
Originally posted by Nightshade:
<strong>

According to the article, the Przewalski wild horse has 66 chromsomes. The domesticated horse has 64 chromosomes. However, despite the genome diffences, the two horses can be crossed and produce fertile offspring. </strong>
If a 66-chromosome horse sperm can successfully fertilize a 64-chromosome horse egg, I'd say V's most recent objection along the lines of a 24-chromosome sperm unable to fertilize a 23-chromosome egg have been laid to rest.
Baloo is offline  
Old 09-05-2002, 12:14 PM   #212
Senior Member
 
Join Date: Jul 2002
Location: California
Posts: 694
Post

Quote:
Originally posted by Skeptical:
<strong>


I'll ask again, do you deny the that the _actual_ appearance of chromosome #2 is in fact as posted by Scigirl? </strong>
Answer: YES

But it is a provisional denial. Please indicate if you don't know what I mean by this term.

As with the other thread, I think you read too much into what I'm saying, Skeptical. Furthermore, you insist that the answer to everything is binary. Zero for no/false, and 1 for yes/true. But surely, many things in life cannot be answered with such precision, eh?


Vanderzyden
Vanderzyden is offline  
Old 09-05-2002, 12:23 PM   #213
Senior Member
 
Join Date: Jul 2002
Location: California
Posts: 694
Post

Quote:
Originally posted by Xixax:
<strong>
I would call you a troll, but you're much longer winded and orders of magnitude more stubborn than any I've seen lately.</strong>
Welcome X!

I will ignore the standard insults and the other redundant content of your post and wait to upon you to substantively contribute evidence to support your claims. Please don't merely refer to the links that others have posted: make an attempt to elucidate a particular point and demonstrate how it serves to answer the question at hand.

Furthermore, I will consider your last statement as an exceptionally flattering comment. I don't care about my reputation--at least not in the way that you are indicating.

As I have said, I could be wrong. That has not been shown. Let us follow the truth wherever it leads, not where we would like it to go.


Thanks!

Vanderzyden

[ September 05, 2002: Message edited by: Vanderzyden ]</p>
Vanderzyden is offline  
Old 09-05-2002, 12:30 PM   #214
Veteran Member
 
Join Date: Aug 2002
Location: Silver City, New Mexico
Posts: 1,872
Post

Quote:
Originally posted by Vanderzyden:
<strong>
Let us follow the truth wherever it leads, not where we would like it to go.
</strong>
Please take your own advice!
wade-w is offline  
Old 09-05-2002, 12:31 PM   #215
Senior Member
 
Join Date: Jul 2002
Location: California
Posts: 694
Post

Quote:
Originally posted by Nightshade:
<strong>Vanderzyden,

Here's something interesting for you to think about. This is in regards to a study mentioned in the same <a href="http://www.gate.net/~rwms/EvoEvidence.html" target="_blank">website</a> that argues for chimp/human chromosome fusion.

According to the article, the Przewalski wild horse has 66 chromsomes. The domesticated horse has 64 chromosomes. However, despite the genome diffences, the two horses can be crossed and produce fertile offspring. This brings about some interesting questions for you:
</strong>
I don't see it on the website. Actually, where may I find the original study?

It seems interesting, but still problematic. But...let's wait until you can point me to something definitive before we discuss it in detail.

Vanderzyden
Vanderzyden is offline  
Old 09-05-2002, 12:41 PM   #216
Veteran
 
Join Date: Aug 2001
Location: Snyder,Texas,USA
Posts: 4,411
Post

VZ - I am not a biologist any more than you, so I will ask all that are here:

What in the sacred name of Gregor Mendel would prevent a 2p and a 2q chromosome in a sperm from lining up one right after the other along a fused 2p/2q chromosome in an ovum? Particularly when all the sequences matched essentially exactly, except for the fusion itself?

You wrote:
Quote:
Answer: YES

But it is a provisional denial. Please indicate if you don't know what I mean by this term.
I know what provisional means. Are you also waiting for more data on whether apples still accelerate toward the center of the Earth when they separate from the tree?
Coragyps is offline  
Old 09-05-2002, 12:45 PM   #217
Regular Member
 
Join Date: Mar 2002
Location: Kentucky
Posts: 472
Post

Quote:
Originally posted by Vanderzyden:
<strong>

Answer: YES

But it is a provisional denial. Please indicate if you don't know what I mean by this term.

</strong>
I understand exactly what provisional means. It means you are hedging. What I cannot understand is why you are hedging on a question of fact. As far as I can tell, you are simpy denying it without any factual basis for doing so.

You say you "provisionally" deny the appearance of human chromosome #2. The only basis I can think of for your denial is that you think Scigirl is lying or the source of her information is lying. The chromosome is what it is. Would it take you being brought to a lab and seeing the chromosome for yourself? If you don't trust that scientists are even telling the truth about a trivially verifiable fact, then I don't see what point there is in any further discussion. If the human chromosome #2 does not look like scientists say, don't you think that someone, somewhere by now would have blown the whistle? I have tried to understand your POV, but at this point it seems to me that you are being stubborn just for the sake of being stubborn.

Quote:
<strong>
As with the other thread, I think you read too much into what I'm saying, Skeptical. Furthermore, you insist that the answer to everything is binary. Zero for no/false, and 1 for yes/true. But surely, many things in life cannot be answered with such precision, eh?</strong>
I think that a question of fact is _always_ a binary. Either there is a ball in the road or there is not. Either the human chromosome #2 looks as reported by Scigirl or it does not. Empirical facts are what they are. You "provisionally" deny what is an observable fact. This observable fact is accepted by all creationists and evolutionists who have studied the question, the only disagreement is on the explanation of the observable fact. You are the only person, as far as I can tell, who has examined the evidence that denies this fact. What's more, you offer no explanation as to why you deny this fact. I don't know what more can be said if you will not even agree on the facts we are discussing.

It would have been better if you had simply said at the beginning of the thread that you thought that the appearance of human chromosome #2 has been faked by scientists. We could have ended the discussion right then. In truth, I'm not sure why you continued with the discussion as you have when you could simply have said "human chromosome #2 doesn't look like that, so no explanation is necessary" and been done.
Skeptical is offline  
Old 09-05-2002, 12:49 PM   #218
Contributor
 
Join Date: Jul 2001
Location: Deep in the heart of mother-lovin' Texas
Posts: 29,689
Post

The 66/64 stuff is on <a href="http://www.gate.net/~rwms/EvoEvidence.html" target="_blank">this site</a> which is linked to from the page Nightshade provided a link to. At (9) it gives the reference to the study. I'll include it here so you don't have to try to figure it out:

Quote:
9. J Reprod Fertil Suppl 1975 Oct;(23):356-70

Cytogenetic studies of three equine hybrids.

Chandley AC, Short RV, Allen WR.

A detailed investigation of testicular meiosis in a mule, a hinny and a Przewalski horse/domestic horse hybrid were made. Abnormalities of pairing were observed in the mule and hinny in most germ cells at the pachytene stage of meiotic prophase, and spermatogenesis was almost totally arrested. A few mature spermatozoa were recovered from the ejaculate and epididymal flushings of the hinny. The Przewalski horse/domestic horse hybrid was fertile and showed normal spermatogenesis. Chromosome banding studies showed a close homology between the karyotypes of the Prezwalski horse (Equus przewalskii, 2n = 66) and the domestic horse (E. caballus, 2n = 64), and it is evident that a single Robertsonian translocation has occurred transforming four acrocentric chromosomes of E. przewalskii into two metacentric chromosomes in E. caballus. The investigations showed that a trivalent is formed at meiosis in the hybrid (2n = 65), segregation from which gives two classes of genetically balanced spermatozoa. Both of these are capable of producing normal offspring if they fertilize the eggs of a domestic mare.

PMID: 1060807 [PubMed - indexed for MEDLINE]
Mageth is offline  
Old 09-05-2002, 12:57 PM   #219
pz
Veteran Member
 
Join Date: Aug 2001
Location: Morris, MN
Posts: 3,341
Post

Quote:
Originally posted by Coragyps:
<strong>VZ - I am not a biologist any more than you, so I will ask all that are here:

What in the sacred name of Gregor Mendel would prevent a 2p and a 2q chromosome in a sperm from lining up one right after the other along a fused 2p/2q chromosome in an ovum? Particularly when all the sequences matched essentially exactly, except for the fusion itself?</strong>
Nothing at all, and that's exactly what happens. I've even seen time-lapse video of mismatched chromosomes lining up exactly as you describe. And as we all know, if you can see it on TV, it must be true.
pz is offline  
Old 09-05-2002, 01:14 PM   #220
Veteran Member
 
Join Date: Sep 2001
Location: Edmonton, Canada
Posts: 2,767
Post

Quote:
Originally posted by Vanderzyden:
<strong>

I don't see it on the website. Actually, where may I find the original study?

It seems interesting, but still problematic. But...let's wait until you can point me to something definitive before we discuss it in detail.
</strong>
My mistake. It's on the the same website, but in this <a href="http://www.gate.net/~rwms/hum_ape_chrom.html" target="_blank">page here.</a>

Here's some info from the site specifically on the <a href="http://www.ansi.okstate.edu/BREEDS/HORSES/PRZEW/index.htm" target="_blank">Przewalski horse.</a>

Quote:
Some authorities feel strongly that the Przewalski horse is the ancestor of all modern breeds. Others point out that it is a different species from the domesticated horse, having 66 chromosomes as compared to the 64 of the domestic horse. They further point out that while crosses between the Przewalski and domestic horses result in a fertile hybrid, the offspring has 65 chromosomes. Subsequent crosses result in 64 chromosomes and bear little resemblance to the Przewalski.
And here is primary reference the site gives:


Quote:
J Reprod Fertil Suppl 1975 Oct;(23):356-70

Cytogenetic studies of three equine hybrids.

Chandley AC, Short RV, Allen WR.

A detailed investigation of testicular meiosis in a mule, a hinny and a Przewalski horse/domestic horse hybrid were made. Abnormalities of pairing were observed in the mule and hinny in most germ cells at the pachytene stage of meiotic prophase, and spermatogenesis was almost totally arrested. A few mature spermatozoa were recovered from the ejaculate and epididymal flushings of the hinny. The Przewalski horse/domestic horse hybrid was fertile and showed normal spermatogenesis. Chromosome banding studies showed a close homology between the karyotypes of the Prezwalski horse (Equus przewalskii, 2n = 66) and the domestic horse (E. caballus, 2n = 64), and it is evident that a single Robertsonian translocation has occurred transforming four acrocentric chromosomes of E. przewalskii into two metacentric chromosomes in E. caballus. The investigations showed that a trivalent is formed at meiosis in the hybrid (2n = 65), segregation from which gives two classes of genetically balanced spermatozoa. Both of these are capable of producing normal offspring if they fertilize the eggs of a domestic mare.
Edit: Arrgh!! Sorry Mageth, once again ya beat me to it!

[ September 05, 2002: Message edited by: Nightshade ]</p>
KnightWhoSaysNi is offline  
 

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Forum Jump


All times are GMT -8. The time now is 03:55 AM.

Top

This custom BB emulates vBulletin® Version 3.8.2
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.