When ancestors sneeze

Love this story on the BBC site today; it's a biology piece about crafty little critters called ERV's (endogenous retro viruses). These are viruses that end up inserted into the very structure of the DNA at the heart of their hosts' cells, once in place they are able to use the mechanisms of that cell to replicate. Sometimes these viruses can be seen at a particular place in a DNA sequence across many generations, i.e. their DNA sequence persists from one generation of host to the next. If you're looking for proof that evolution happens then you need look no further than your own DNA, embedded in it is an ancient virus that infected one of our distant ancestors over 100 million years ago, you can find the exact same virus "code" in most mammals at exactly the same spot in our respective DNA chains faithfully reproduced over the aeons clearly demonstrating common descent (i.e. we share a common ancestor with all other mammals).