A prion is a protein that can fold certain other proteins into copies of itself. There are several known varieties of prions, most of them associated with certain diseases. It's not alive in the traditional sense, but given the right material it can "reproduce".

One interesting point about prions that's related to this story is that they're much hardier than bacteria and other living things. They can be heated, frozen, etc. and they can still come out of dormancy years later and start acting up again. That might make it a good candidate for a simple life precursor in harsh environments where other organic molecules don't last very long.