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Author Topic:   Endosymbiont theory wrong?
blitz77
Inactive Member


Message 1 of 43 (16890)
09-08-2002 5:33 AM


quote:
Scots scientists challenge rules of evolution

Frank Urquhart

A MAJOR discovery of a so-called missing link by researchers at a Scottish university has raised serious doubts about how the cells in the human body and other forms of life first evolved.

Until now, it has been accepted thinking among biologists that the complex cells of the human body evolved from primitive cells such as bacteria. These contained only a tiny specialised nucleus which held and protected the genes of every cell.

Only later in evolution, it was believed, did cells acquire hundreds of mitochondria - the minute energy generators which power and keep complex cells alive.

But that view is now being challenged by scientists at Dundee University and researchers at the National History Museum in London, who have used state-of-the-art microscopy techniques to identify an unexpected link in the evolutionary process.

They have discovered tiny mitochondria lying undetected in the cells of primitive parasites.

Dr John Lucocq, of Dundee University, said the team’s discovery represented a new missing link in scientific knowledge.

He added: "Scientists believe that the complex cells of our body evolved from simple cells like bacteria.

"Primitive cells first evolved a tiny specialised compartment called a nucleus - which is basically a bag for holding and protecting the genes of every cell.

"Only later in evolution did they acquire hundreds of minute energy generators that keep our complex cells alive - better known to biologists as mitochondria.

"The main evidence for these two steps in evolution came from primitive parasite cells that contain a nucleus but show no traces of the power-generating mitochondria."

He said his team began to have doubts about accepted scientific thinking when recent research suggested that the typical components of a cell’s "power pack" - mitochondria - might be present in primitive cells. Advanced microscopy techniques confirmed their suspicions.

Dr Lucocq said: "We used powerful state-of-the-art high-resolution electron microscopes at the University of Dundee to reveal mitochondria that were less than ten times smaller than the mitochondria of other cells.

"We now think the tiny mitochondria of these parasites are ‘left-overs’ that have shrunk during evolution, making them more difficult to recognise."

He added: "This discovery changes the way we think about how cells evolved.

"If these parasites are a sort of living fossil, then this is a bit like a ‘missing link’ human ancestor turning out to be a present day human."--The Scotsman


Or if you want the nature article, it is here

[This message has been edited by blitz77, 09-08-2002]


Replies to this message:
 Message 2 by Itzpapalotl, posted 09-08-2002 7:06 AM blitz77 has not yet responded

  
Itzpapalotl
Inactive Member


Message 2 of 43 (16897)
09-08-2002 7:06 AM
Reply to: Message 1 by blitz77
09-08-2002 5:33 AM


This paper really doesn't challenge endosybiosis at all it says that these parasites did't diverge from other eukaryotes before the gain of mitochondria. In fact it makes sense that a parasite that gets all of its energy from its host would have smaller or vestigial mitochondria. There is alot of evidence in favour of the bacterial origin of chloroplasts and mitochondria such as their own circular DNA, bacterial ribosomes, the phylogenetic analysis of many proteins and the recent discovery of bacteria living inside other bacteria.

here is the full reference and abstract:

Nature 2002 Aug 22;418(6900):865-9
A mitochondrial remnant in the microsporidian Trachipleistophora hominis.
Williams BA, Hirt RP, Lucocq JM, Embley TM.

Microsporidia are obligate intracellular parasites of several eukaryotes. They have a highly complex and unique infection apparatus but otherwise appear structurally simple. Microsporidia are thought to lack typical eukaryotic organelles, such as mitochondria and peroxisomes. This has been interpreted as support for the hypothesis that these peculiar eukaryotes diverged before the mitochondrial endosymbiosis, which would make them one of the earliest offshoots in eukaryotic evolution. But microsporidial nuclear genes that encode orthologues of typical mitochondrial heatshock Hsp70 proteins have been detected, which provides evidence for secondary loss of the organelle or endosymbiont. In addition, gene trees and more sophisticated phylogenetic analyses have recovered microsporidia as the relatives of fungi, rather than as basal eukaryotes. Here we show that a highly specific antibody raised against a Trachipleistophora hominis Hsp70 protein detects the presence, under light and electron microscopy, of numerous tiny ( approximately 50 x 90 nm) organelles with double membranes in this human microsporidial parasite. The finding of relictual mitochondria in microsporidia provides further evidence of the reluctance of eukaryotes to lose the mitochondrial organelle, even when its canonical function of aerobic respiration has been apparently lost.


This message is a reply to:
 Message 1 by blitz77, posted 09-08-2002 5:33 AM blitz77 has not yet responded

Replies to this message:
 Message 3 by peter borger, posted 09-09-2002 3:59 AM Itzpapalotl has responded

  
peter borger
Member (Idle past 6004 days)
Posts: 965
From: australia
Joined: 07-05-2002


Message 3 of 43 (16943)
09-09-2002 3:59 AM
Reply to: Message 2 by Itzpapalotl
09-08-2002 7:06 AM


dear I,

You say:
"This paper really doesn't challenge endosybiosis at all..

I say:
Of course it doesn't, because nothing can challenge --let alone falsify-- evolution theory. I think I will let you dream on"

And you say:
"..it says that these parasites did't diverge from other eukaryotes before the gain of mitochondria. In fact it makes sense that a parasite that gets all of its energy from its host would have smaller or vestigial mitochondria."

I say:
It makes sense indeed, but it cannot be used to support evolution. If it demonstrates anything it is de-evolution.
By the way, there are no such thing as vestiges. That is 19th century blahblah.

And if you wanna discuss the "fairytale of the endosymbiont" you have just found your man.

Best wishes,
Peter


This message is a reply to:
 Message 2 by Itzpapalotl, posted 09-08-2002 7:06 AM Itzpapalotl has responded

Replies to this message:
 Message 4 by Peter, posted 09-09-2002 6:24 AM peter borger has responded
 Message 5 by Itzpapalotl, posted 09-09-2002 12:53 PM peter borger has responded
 Message 20 by derwood, posted 10-01-2002 1:58 PM peter borger has responded

  
Peter
Member (Idle past 2262 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 4 of 43 (16954)
09-09-2002 6:24 AM
Reply to: Message 3 by peter borger
09-09-2002 3:59 AM


quote:
Originally posted by peter borger:

And you say:
"..it says that these parasites did't diverge from other eukaryotes before the gain of mitochondria. In fact it makes sense that a parasite that gets all of its energy from its host would have smaller or vestigial mitochondria."

I say:
It makes sense indeed, but it cannot be used to support evolution. If it demonstrates anything it is de-evolution.


... and your use of a term such as 'de-evolution' shows that
you have a complete lack of understanding wrt evolution in the
first place.


This message is a reply to:
 Message 3 by peter borger, posted 09-09-2002 3:59 AM peter borger has responded

Replies to this message:
 Message 8 by peter borger, posted 09-11-2002 3:33 AM Peter has responded

  
Itzpapalotl
Inactive Member


Message 5 of 43 (17007)
09-09-2002 12:53 PM
Reply to: Message 3 by peter borger
09-09-2002 3:59 AM


Evolution is falsifiable, for example if new species couldn't form or new genes hadn't been seen to be created by natural processes it would be impossible for evolution to occur. Ayway i thought we were talking about endosymbiosis.

"If it demonstrates anything it is de-evolution.
By the way, there are no such thing as vestiges. That is 19th century blahblah."

evolution is not necessarily an increase in complexity, greater efficiency is also important and this includes the loss of unecessary parts and even evolving towards inevitable extinction (for example adapting to a short lived ecological niche). How would you describe the smaller remains of an organelle that has lost most of its original function apart from relics or vestiges. Degeneration of genes and structures in parasites and symbionts has been demonstrated many times.

The research is nothing new it just confirms earlier work (Hirt RP, Healy B, Vossbrinck CR, Canning EU, Embley TM. A mitochondrial Hsp70 orthologue in Vairimorpha necatrix: molecular evidence that microsporidia once contained mitochondria. Curr Biol. 1997 Dec 1;7(12):995-8.PMID: 9382838)

ok lets discuss all the evidence in favour of this 'fairytale'.
Here is just some of it:

Both mitochondria and chloroplasts have their own genome and it resembles that of prokaryotes not that of the nuclear genome.

Both genomes consist of a single circular molecule of DNA.
There are no histones associated with the DNA.

The mitochondrial genome contains type II introns which have similarities to those found in bacterial but not eukaryotic genomes. This was used by answers in genesis as evidence against the bacterial origin of mitochondria!
( http://www.answersingenesis.org/docs2/4341_endosymbiont.asp ).

Both mitochondria and chloroplasts have their own protein-synthesizing machinery, and it resembles that of prokaryotes not that found in the cytoplasm of eukaryotes.
Their ribosomal RNA (rRNA) and the structure of their ribosomes resemble those of prokaryotes, not eukaryotes.

The first amino acid of their transcripts is always fMet as it is in bacteria (not methionine [Met] that is the first amino acid in eukaryotic proteins).

A number of antibiotics (e.g., streptomycin) that act by blocking protein synthesis in bacteria also block protein synthesis within mitochondria and chloroplasts. They do not interfere with protein synthesis in the cytoplasm of the eukaryotes.
Conversely, inhibitors (e.g., diphtheria toxin) of protein synthesis by eukaryotic ribosomes do not - sensibly enough - have any effect on bacterial protein synthesis nor on protein synthesis within mitochondria and chloroplasts.

The antibiotic rifampicin, which inhibits the RNA polymerase of bacteria, also inhibits the RNA polymerase within mitochondria. It has no such effect on the RNA polymerase within the eukaryotic nucleus.

it is even possible to identify the type of bacteria that was the likely ancestor of mitochondria, the most similar today being the alpha-probacteria Rickettsia. This is due to the similarities of the genes for proteins such as cytochrome b and cytochrome c oxidase and ATP production in Rickettsia is the same as that in mitochondria. Hsp60 homologues from alpha-purple bacteria (such as Rickettsia) and mitochondria contain unique sequences that are not found in other prokaryotes. Rickettsia also have a carrier-mediated transport system which allows specific transport of ADP and ATP. The ATP/ADP translocases are homologous between mitochondria and Rickettsia. Its clear from many differnt pieces of evidence that mitochondria and Rickettsia have a commmon ancestor.

The fact that no bacteria were thought to live inside other bacteria was interpreted as evidence against endosymbiosis, but the discovery of secondary endosybitic bacteria within bacteria found inside mealybugs (Pseudococcidae) proves this not to be the case. These endosybionts were found to have a double membrane surrounding them like mitochondria do.

There is dispute about the details and timing of the various events of endosymbiosis but the theory has been proved to be correct even though most biologists were sceptical at first when it was proposed in its modern form by Dr Lynn Margulis.

from this and other evidence i believe the endosybiosis to be a fact. as Stephen Jay Gould put it "In science "fact" can only mean "confirmed to such a degree that it would be perverse to withhold provisional consent.""

shortened reference list:

The ncbi human mitochondria page:
http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/framik?db=Genome&gi=12188

type II introns:
http://www.fp.ucalgary.ca/group2introns/wherefound.htm

Mealybug [beta]-proteobacterial endosymbionts contain [gamma]-proteobacterial
symbionts. von Dohlen, Carol D.; Kohler, Shawn*; Alsop, Skylar T.; McManus, William R.
Nature Volume 412(6845) 26 July 2001 pp 433-436.

Evolutionary relationship of Rickettsiae and mitochondria
Victor V. Emelyanov. FEBS Letters 501 (2001) 11-18.

Degenerative Minimalism in the Genome of a Psyllid Endosymbiont
MARTA A. CLARK,1 LINDA BAUMANN,1 MYLO LY THAO,1 NANCY A. MORAN,2
AND PAUL BAUMANN. JOURNAL OF BACTERIOLOGY, Mar. 2001, p. 1853–1861.

Origin and Evolution of the Mitochondrial Proteome. C. G. KURLAND1,2* AND S. G. E. ANDERSSON. MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS,Dec. 2000, p. 786–820 Vol. 64, No. 4

The genome sequence of Rickettsia prowazekii and the origin of mitochondria
Siv G. E. Andersson*, Alireza Zomorodipour*, Jan O. Andersson*, Thomas Sicheritz-Ponte¬ n*, U. Cecilia M. Alsmark*, Raf M. Podowski*, A. Kristina Na» slund*, Ann-SoÆe Eriksson*, Herbert H. Winkler² & Charles G. Kurland. NATURE |VOL 396 | 12 NOVEMBER 1998 .


This message is a reply to:
 Message 3 by peter borger, posted 09-09-2002 3:59 AM peter borger has responded

Replies to this message:
 Message 6 by mark24, posted 09-10-2002 9:55 PM Itzpapalotl has responded
 Message 7 by peter borger, posted 09-11-2002 3:07 AM Itzpapalotl has not yet responded
 Message 17 by peter borger, posted 09-30-2002 11:11 PM Itzpapalotl has responded

  
mark24
Member (Idle past 3534 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 6 of 43 (17132)
09-10-2002 9:55 PM
Reply to: Message 5 by Itzpapalotl
09-09-2002 12:53 PM


Itzpapalotl,

Excellent post. Can I have permission to store those evidences you present ( with cites) in a word doc, so as I can shamelessly plagiarise you at a later date?

(I will of course credit you ),

Mark

------------------
Occam's razor is not for shaving with.


This message is a reply to:
 Message 5 by Itzpapalotl, posted 09-09-2002 12:53 PM Itzpapalotl has responded

Replies to this message:
 Message 10 by Itzpapalotl, posted 09-11-2002 7:12 AM mark24 has responded

  
peter borger
Member (Idle past 6004 days)
Posts: 965
From: australia
Joined: 07-05-2002


Message 7 of 43 (17141)
09-11-2002 3:07 AM
Reply to: Message 5 by Itzpapalotl
09-09-2002 12:53 PM


dear I,
Thanks for the references.
I will have a close look at them.
Best wishes.
Peter

This message is a reply to:
 Message 5 by Itzpapalotl, posted 09-09-2002 12:53 PM Itzpapalotl has not yet responded

  
peter borger
Member (Idle past 6004 days)
Posts: 965
From: australia
Joined: 07-05-2002


Message 8 of 43 (17144)
09-11-2002 3:33 AM
Reply to: Message 4 by Peter
09-09-2002 6:24 AM


Dear Peter,

How can somebody understand something that isn't?

Best wishes.
Peter


This message is a reply to:
 Message 4 by Peter, posted 09-09-2002 6:24 AM Peter has responded

Replies to this message:
 Message 9 by Peter, posted 09-11-2002 6:10 AM peter borger has responded

  
Peter
Member (Idle past 2262 days)
Posts: 2160
From: Cambridgeshire, UK.
Joined: 02-05-2002


Message 9 of 43 (17154)
09-11-2002 6:10 AM
Reply to: Message 8 by peter borger
09-11-2002 3:33 AM


quote:
Originally posted by peter borger:
Dear Peter,

How can somebody understand something that isn't?

Best wishes.
Peter


Perhaps I should have said the Theory of Evolution ... but your
response avoids answering the criticism levelled.


This message is a reply to:
 Message 8 by peter borger, posted 09-11-2002 3:33 AM peter borger has responded

Replies to this message:
 Message 12 by peter borger, posted 09-11-2002 8:39 PM Peter has responded

  
Itzpapalotl
Inactive Member


Message 10 of 43 (17156)
09-11-2002 7:12 AM
Reply to: Message 6 by mark24
09-10-2002 9:55 PM


mark24
feel free to plagiarise me although you should probably also credit: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Endosymbiosis.html who i forgot to mention in my original post.

This page is critical of endosymbiosis although not from a creationist perspective: http://www.gwu.edu/~darwin/BiSc151/Eukaryotes/Eukaryotes.html
if anyone knows any other sites or articles that have criticisms of endosymbiosis i would be interested in reading them.


This message is a reply to:
 Message 6 by mark24, posted 09-10-2002 9:55 PM mark24 has responded

Replies to this message:
 Message 11 by mark24, posted 09-11-2002 6:21 PM Itzpapalotl has not yet responded

  
mark24
Member (Idle past 3534 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 11 of 43 (17193)
09-11-2002 6:21 PM
Reply to: Message 10 by Itzpapalotl
09-11-2002 7:12 AM


quote:
Originally posted by Itzpapalotl:
mark24
feel free to plagiarise me although you should probably also credit: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Endosymbiosis.html who i forgot to mention in my original post.

This page is critical of endosymbiosis although not from a creationist perspective: http://www.gwu.edu/~darwin/BiSc151/Eukaryotes/Eukaryotes.html
if anyone knows any other sites or articles that have criticisms of endosymbiosis i would be interested in reading them.


Itzpapalotl,

Thanks for the links.

Mark


This message is a reply to:
 Message 10 by Itzpapalotl, posted 09-11-2002 7:12 AM Itzpapalotl has not yet responded

  
peter borger
Member (Idle past 6004 days)
Posts: 965
From: australia
Joined: 07-05-2002


Message 12 of 43 (17206)
09-11-2002 8:39 PM
Reply to: Message 9 by Peter
09-11-2002 6:10 AM


Dear Peter,

Nobody understands the ToE at the molecular level, or any level. Why? Because evolution doesn't exist. Better name for the wat the ToE stands for would be Theory of Variation-induction (or something like that). Scientists are discovering that evolution as it was set up by the NDT-ers cannot work.

In addition, why do you think that websites like these are around? If evolution was a fact --as claimed so often by proponents-- these sites wouldn't exist. Ever encountered a site for "flat-versus-round" earth-discussions? Of course not. There is scientific consensus about the earth. Not about evolution, since compelling evidence is lacking.

I will always object to the nihilism underlying NDT. It's my main goal in life.

best wishes,
Peter


This message is a reply to:
 Message 9 by Peter, posted 09-11-2002 6:10 AM Peter has responded

Replies to this message:
 Message 13 by Mister Pamboli, posted 09-12-2002 12:21 AM peter borger has not yet responded
 Message 14 by Mammuthus, posted 09-12-2002 10:34 AM peter borger has not yet responded
 Message 15 by Andya Primanda, posted 09-13-2002 5:43 AM peter borger has not yet responded
 Message 16 by Peter, posted 09-18-2002 3:15 AM peter borger has not yet responded

  
Mister Pamboli
Member (Idle past 5916 days)
Posts: 634
From: Washington, USA
Joined: 12-10-2001


Message 13 of 43 (17216)
09-12-2002 12:21 AM
Reply to: Message 12 by peter borger
09-11-2002 8:39 PM


quote:
Originally posted by peter borger:
I will always object to the nihilism underlying NDT. It's my main goal in life.

Would you care to expand in another topic? On nihilism and neo-Darwinism, I mean, not on your life goals. :-)

What form does this nihilism take? Do you believe it to be a necessary aspect of the theory, and if so, why? Could be quite interesting.


This message is a reply to:
 Message 12 by peter borger, posted 09-11-2002 8:39 PM peter borger has not yet responded

  
Mammuthus
Member (Idle past 4814 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 14 of 43 (17266)
09-12-2002 10:34 AM
Reply to: Message 12 by peter borger
09-11-2002 8:39 PM


quote:
Originally posted by peter borger:
Dear Peter,

Nobody understands the ToE at the molecular level, or any level. Why? Because evolution doesn't exist. Better name for the wat the ToE stands for would be Theory of Variation-induction (or something like that). Scientists are discovering that evolution as it was set up by the NDT-ers cannot work.

In addition, why do you think that websites like these are around? If evolution was a fact --as claimed so often by proponents-- these sites wouldn't exist. Ever encountered a site for "flat-versus-round" earth-discussions? Of course not. There is scientific consensus about the earth. Not about evolution, since compelling evidence is lacking.

I will always object to the nihilism underlying NDT. It's my main goal in life.

best wishes,
Peter


Oh yeah Peter? Here are some links to flat earth proponents

http://www.hist.unt.edu/09w-ar7n.htm

Nobody understands gravity either...it would be better named I did not float into space this morning theory.


This message is a reply to:
 Message 12 by peter borger, posted 09-11-2002 8:39 PM peter borger has not yet responded

  
Andya Primanda
Inactive Member


Message 15 of 43 (17338)
09-13-2002 5:43 AM
Reply to: Message 12 by peter borger
09-11-2002 8:39 PM


quote:
Originally posted by peter borger:
Dear Peter,
Nobody understands the ToE at the molecular level, or any level. Why? Because evolution doesn't exist. Better name for the wat the ToE stands for would be Theory of Variation-induction (or something like that). Scientists are discovering that evolution as it was set up by the NDT-ers cannot work.

Maybe you should work together with Syamsu? He's proposing a general theory of reproduction and you're proposing a theory of variation.

Let me think for a while... some scientists had done this before in the 1940s and they come up with... NDT?


This message is a reply to:
 Message 12 by peter borger, posted 09-11-2002 8:39 PM peter borger has not yet responded

  
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