The Key to Evolution — Peter hamilton

Jobal and Elmia Frosher are a relatively normal couple in their fifties. At least they believe that they are normal. This camping trip is to be a typical outing, until the probe lands near their campsite. The fact that an errant probe from space should land so close to them is odd enough, but this probe, returning from a rendezvous with a comet, is carrying a virus older than life itself! This virus has the ability to change DNA and even the course of history! Are Jobal and Elmia strong enough to help bring the human race through these changes and into the future, or will this be the final chapter for all the people of earth?