Don't know if this is a popular idea, but is it possible a virus could introduce new sequences? The new sequences wouldn't have to be functional, and it appears that most DNA is nonfunctional.
ok, ill bite. the DNA is introduced by a virus. where did the RNA come from for the virus then?
as for DNA being "mostly nonfunctional" how would that correlate with animals that are missing a single gene becoming different in appearance, and structure? they are still said "animal" but with something wrong. that something wrong becomes visable or chemical, but it does show.
just an honest question, though the idea of a virus introducing DNA does intrigue me. any sources?