This is one of the thousands of evidences for our evolutionary relationship with the other ape species.

"We also harbor dead genes that came from other species, namely viruses. Some, called 'endogenous retroviruses' (ERVs), can make copies of their genome and insert them into the DNA of species they infect. (HIV is a retrovirus.) If the viruses infect the cells that make sperm and eggs, they can be passed on to future generations. The human genome contains thousands of such viruses, nearly all of them rendered harmless by mutations. They are the remnants of ancient infections. But some of these remnants sit in exactly the same location on the chromosomes of humans and chimpanzees. These were surely viruses that infected our common ancestor and were passed on to both descendants. Since there is almost no chance of viruses inserting themselves independently at exactly the same spot in two species, this points strongly to common ancestry."

-- Jerry Coyne, University of Chicago biologist, author of Why Evolution Is True and Faith Versus Fact