Mammals like ourselves pass our genes ‘vertically’ from parent to child. But bacteria aren’t quite so limited; they have mastered the art of gene-swapping and regularly transfer DNA ‘horizontally’ from one cell to another. This “horizontal gene transfer” has been largely viewed as a trademark of single-celled organisms, with few examples among animals and plants. That is, until now.

A group of American researchers have discovered a group of genetic sequences that have clearly jumped around the genomes of several mammals, one reptile and one amphibian. It’s the most dramatic example yet that horizontal genetic transfer outside of the bacterial realm is more common than we thought, and has helped to shape the evolution of animals. Meet the Space Invaders,