Retroviruses carry their genetic blueprint in the form of RNA, which they use to synthesize DNA—the reverse of the usual process. This makes it possible for their genetic material to become a permanent part of the genes of an infected cell. An endogenous retrovirus is a retrovirus-like sequence found in an organism’s genome that is thought to constitute the remains of a true retrovirus absorbed through evolution. In humans, endogenous retroviruses are suspected of involvement in what diseases? Discuss