IamJoseph writes:
Re: "Retroviruses: are these limited to the 3rd rock from the sun - and why so?"
Obviously, contesting darwin's cross-specie theory is not an easy task. I felt, one way to respond to retroviruses as evidence, is to challenge adaptation as a constant by its limitations. That's all #61 asks.
Joseph from reading your last few posts I don't think you are understanding the importance of "retroviruses" as a compelling evidence of past evolutionary action.
Endogenous Retrovirus DNA is a subject that I recently became aware of myself. I don't have much formal education in biology, so I had to slog through the jargon to understand, but it was worth it and I am continuing to study this issue.
Let me try to explain, and anyone with more background please correct me where I error.
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.
Edited by iceage, : No reason given.
Edited by iceage, : No reason given.
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