The Human Brain Owes Its Existence to a Prehistoric Pandemic

some retrovirus infected the chimps and mutated their genes and their brains got maxed out.

There are not many retroviruses around but there are some. MMTV/HMTV retrovirus are suspected to cause breast cancer.

This isn't very carefully edited: chimpanzees are not our closest evolutionary ancestor. The whole article is kind of pale, washed out.