The DNA sequence that explains why humans and great apes have no tails. A common trait in much of the animal kingdom, the tail is present in all mammals - including sapiens - at some point in embryonic development.
In the case of humans, gorillas or orangutans, it disappears at the end of gestation. This Wednesday, Nature magazine dedicates its cover to research by scientists at the Grossman School of Medicine in New York that reveals how the insertion of a mobile genetic sequence would be related to its loss.