Searching for SIV in Monkey Mummies

Abstract To trace genetic changes that could have made SIV into a harmless virus of African green monkeys and sooty mangabeys, we needed to find SIV in an ancient and possibly harmful form. How can we do this? When SIV infects white blood cells, its RNA converts to DNA and moves into the host cell genome. There it stays-harmless or not-for the life of the host, and sometimes in postmortem remains. Since SIV infects monkeys at reproductive age, its presence in host cells should persist as the animal ages, reaching a high level by the end of a typical life span. So our best chance to find ancient SIV was to find SIV-infected adult monkeys that died in ancient times but retained tissue that might contain white blood cells. In the DNA of such monkey cells we might find some integrated stretches of SIV DNA. As this chapter will tell, monkey mummies twenty-five hundred to five thousand years old can be found and studied. Techniques exist to recover SIV DNA from the DNA of ancient monkeys, to amplify the viral material in the test tube, and to analyze its virulence and other characteristics. But before one can study ancient SIV DNA, one must find the right monkeys: