It used to be thought that only a certain kind of virus could get into our genome and it's called a retrovirus and that's a virus that might be HIV for example.

If the world goes crazy for a lovely fossil, that's fine with me. But if that fossil releases some kind of mysterious brain ray that makes people say crazy things and write lazy articles, a serious swarm of flies ends up in my ointment.

The reason that viruses are so hard to fight, the reason for example we need a flu virus every year is that they evolve very fast.

At long last, we may be returning to the original two-sided sense of the word virus, which originally signified either a life-giving substance or a deadly venom. Viruses are indeed exquisitely deadly, but they have provided the world with some of its most important innovations. Creation and destruction join together once more.

There is some research that suggests that viruses like the flu are really actually kind of at the razor's edge when it comes to mutation. They're mutating so fast that if they mutated much faster they would actually develop a lot of harmful mutations that could slow them down and cripple them and eventually literally drive them extinct.

Over millions of years the viruses in our genome mutate more and more so the look less and less and less recognizable as viruses and so if there was a virus that infected our pre mammal ancestors like 250 million years ago, which it probably did, we can't see it because it just looks totally random.

Borna virus is not a retrovirus. It doesn't actually insert its own genes into our cells. What it does is just hangs out near our DNA and uses some of the molecular machinery to copy itself.