Nearly all organisms contain pieces of DNA that do not really belong to them. These "transposable elements", so called because they are capable of moving around within and between genomes, generally represent a drain on the host's resources and in certain cases may lead directly to disease, e.g. when they insert themselves within an essential […]

They are tiny, ugly, disease-carrying little blood-suckers that most people have never seen or heard of, but a new discovery in a one-of-a-kind fossil shows that "bat flies" have been doing their noxious business with bats for at least 20 million years. […]