Genetic comparison with chimps suggests that losing chunks of DNA – including one associated with penis spines and facial whiskers – played a crucial role in making us human. Scientists have identified a clutch of subtle genetic changes that have shaped our minds and bodies into the unique form that sets humans apart from chimpanzees and the rest of the animal kingdom. The work by researchers in the US represents a landmark in a search that has occupied philosophers and scientists for millennia and one that goes to the heart of understanding what it means to be human. The findings...