DNA that has been recovered from archaeological and palaeontological remains makes it possible to go back in time and study the genetic relationships of extinct organisms to their contemporary relatives. This provides a new perspective on the evolution of organisms and DNA sequences. However, the field is fraught with technical pitfalls and needs stringent criteria to ensure the reliability of results, particularly when human remains are studied.

Fossils of the largest known bird, an extinct flightless predator with a skull the size of a horse’s and a menacing beak like an eagle’s, have been discovered in Argentina, paleontologists reported last week.

Implact of Google on libraries and the real changes occurring due to the Internet.