We used to think the ‘sex’ of an animal was clearly defined by its chromosomes. But it’s way more complicated than it seems.

THE complete sequence of the human X chromosome was published in Nature this week. The work shows that large segments of it match parts of normal chromosomes in birds, confirming the X chromosome’s ...

The Max Planck team measured the lifespans of 1,176 wild creatures. Female mammals, the analysis showed, live 13% longer on ...

A greater flamingo in Mallorca, Spain. Unraveling a genetic mystery revealed that flamingos and doves are more distantly related than previously thought. An enormous meteor spelled doom for most ...