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Author Topic:   Endogenous retroviral elements as proof of common descent
Doddy
Member (Idle past 5909 days)
Posts: 563
From: Brisbane, Australia
Joined: 01-04-2007


Message 1 of 2 (409719)
07-10-2007 11:13 PM


My thread, Most convincing evidence for evolutionary theory has been hijacked by this topic. While it is interesting and related to my topic, a prolonged discussion on it isn't required for that thread. So, I am moving the discussion to here.
I shall first quote what iceage said to explain the topic in post 72.
iceage writes:
In simple terms, Endogenous Retrovirus DNA are fossilized molecular relics of far distant infections of a retrovirus that inserted its DNA into a germ line cell. Retroviruses are viruses that convert its own RNA into DNA and then used the cell's existing DNA->RNA->Protein machinery to reproduce itself. The term "retro" comes from the fact that this class of viruses convert its RNA into DNA which is the reverse of the normal transcription form DNA -> RNA. Other viruses just take the short cut and insert their RNA into the RNA->protein conversion process. The exact details are complex but overall implications are profound so let me continue.
Typically retroviruses infect soma cells, but on occasion they will effect a germ line cell and the inserted DNA gets swept away in the organism reproduction process. For a variety of reasons this inserted virus DNA typically does not cause an infection in the organism progeny. However, and this is important, when the inserted DNA information finds its way into the replication process it becomes preserved.
Interestingly bits of information encoded in DNA can have durability that exceeds that of mountains and solid rock. That is, the information becomes renewed in each subsequent reproduction cycle, and if replication is successful, this information can outlasted continents, as the bit of information, useful or not, becomes preserved in subsequent related species.
By examining the DNA code of organisms, the finger prints of these infections can be identified because of their very unique signature. In addition, to the signature the *location* within the genome is noted. Now when these finger prints are looked for in the genomes of related species they can be found in the very same locations!
As an example, there are many many identified Endogenous Retrovirus DNA in humans and our closest living relatives Chimpanzees. To a less extent we and Chimps, share Endogenous Retrovirus DNA with other old world primates in exactly the same hierarchy, that other lines of reasoning would indicate. And as expected we share even fewer Endogenous Retrovirus DNA with the new world primates, which are more distantly related to humans, Chimps and old world primates.
This is truly a stunning find and a powerful tool to prove and detect common ancestry!
As a very simple example, if a teacher was trying to detect plagiarisms in a term paper and if she finds a grammatical error in a paper and she recognizes that this error exists in some original work she could become quite confident that this student copied the original work since the probability of such an error occurring independently is very great.
IamJoseph disagrees with this, as evident in post 75.
IamJoseph writes:
Now see that a certain virus with a specific signature (reverse mode rna-dna action), attacked numerous life forms (different species)- and let us assume also that the 'retrovirus' strand on all life forms is from an equivalent same source and period: would you still conclude that cross-species is proof positive here? No you cannot when seen in this perspective, anymore than deeming a 'hair' folicle on two different animals as proof. That a virus is embedded in dna, and a hair on the skin, does not change the principle of the logic - the equity of its spacetime does not prove a direct cross-specie subsequence. The issue becomes more encumbent when we are told this virus imprint remains intact - which means it is still around now, and can attack an oak tree or a zebra, and perhaps even some food left open in a kitchen table.
I summarised in post 99, in a reply to IamJoseph, with this picture:
and challenged IaJ with this:
Doddy writes:
So, what are the implications for our differing opinions. You can either show me a virus that can affect both humans and chimps, or make an appeal to a past virus that could affect both humans and chimps. However, if you make such an appeal to the past, you must provide evidence, or you will be doing the very thing that you believe evolutionists are doing - making conclusions without the evidence to support it.
IaJ couldn't offer a retrovirus specifically, but given that some other viruses can have broad host ranges, I accepted the possibility that a cross-species retrovirus may exist (or have existed).
Thus, I offered another investigation to distinguish between IaJ's opinion and my own: location of the retroviral elements:
Doddy writes:
To go back to the analogy that iceage brought up, we see this in two different documents.
quote:
Fourscore and seven years ago our fathers brought forth on this continent, a new nation, conceived,,,,,,,,,,,,,,,, in Liberty, and dedicated to the proposition that all men are created equal.
If you had shown me a cross-kind retrovirus, you would have shown, in this example, that both authors of these documents have a sticky comma button on their keyboard. Now you have to give an explanation as to why it got stuck in the same spot in such a big document.
That's where it stands now. Further discussion, of which I'm sure there will be much, can now come to this thread, leaving my other one to do the job for which I created it.

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Message 2 of 2 (409732)
07-10-2007 11:51 PM


Thread copied to the Endogenous retroviral elements as proof of common descent thread in the Biological Evolution forum, this copy of the thread has been closed.

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