Re: So you have nothing!
I think that the reference to ERV's (Endogenous RetroViruses), is grasping at straws for either cause... ERV's do not "prove" anything but that they can persist in the genome of their host for long periods of time.
In addition, as you have pointed out, they tend to have an affinity for a similar loci. This should not be surprising at all. Most virus, bacteria, etc. exhibit preferred affinities. Considering that HERV's (Human Endogenous RetroViruses) are believed to comprise 8% of the human genome, what is so surprising that some of them also show up in other mammals, most specifically as you referenced, other primates? consider that the human genome and chimp genome are only separated by about 3% in differences.
Also consider that ERV's exist in both the human and the primate (choose one), including the chimp, that do not occur, or show up in the other. They could have easily originated through cross species viral infection where this was possible, etc.
The hows and whys of infection, and eventual mutation of a host DNA by an ERV is subjective and theoretical. Sure, man can artificially introduce and speculate on the action... this remains mere speculation though. The artificial introduction can also cause misinterpretation of the data by a future generation that may not have realized the cause was human
Genetically-Modified "experimentation".
Still gives pause to this all happening (human interference) before and Beauchamp's idea of pleomorphism (seeing as how life on this planet, endures similar environmental stressors) being a bit more plausible. It also tends to beg the question, is an increased activity of ERV's responsible for the increase in human ails? If so, what, or how are the ERV's activated? Created? Bet it has to do with environmental stressors, including diet.
We should ask for evolutionary clarification on this from evolutionists (perhaps you?) by injecting that phylogenetic evidence for endogenous retroviruses in plant genomes has been found as well... a little more difficult to explain... perhaps the animals eat the plants and the ERV then spreads via plant... or perhaps the animal dies, then feeds the plant which then absorbs and integrates the ERV... the direction will likely never be known with 100% certainty, so I believe we are back to square one... no irrefutable proof for either "theory".
How would you explain these phenomena?
grz-