Back to the point of
nothing in biology making sense except in the light of evolution, a recent survey has shown that as much as 8 percent of the human genome is made up of
endogenous viruses. The existence of endogenous viruses has been known for a long time (with viral genes providing proteins key to survival, including surface proteins that are key to the functioning of the placenta) but-- to put that number in perspective-- the percentage of the human genome that actually codes for protein is around 2% or less--
the viruses that have accumulated over evolutionary history take up 4 times as much DNA as the DNA that actually builds us!
http://www.popsci.com/science/articl...-schizophrenia
http://www.theness.com/neurologicablog/?p=1466
There is no hope of understanding and curing diseases without studying and understanding (as well as is possible) evolution-- especially when most of our antibiotics that were once considered "wonder drugs" are quickly becoming useless as their targets
evolve resistance.