In 2001, when two separate organisations laid bare, for the first time, the DNA structure of our human genome, it revealed a deeply paradoxical truth.  Where we expected some 100,000 genes coding for the same number of proteins, just 1.5% of the DNA coded for just 20,000 proteins.  Meanwhile, almost half our DNA is viral - with a genetic structure very similar to the genome of HIV-1, the viral cause of AIDS.  What does this mean in terms of the story of our  human evolution?  In Virolution, Frank Ryan explains the remarkable story of how this came about.. and what it means.