ARCHAEOLOGISTS unearth potsherds, palaeontologists dig up fossils, and now geneticists armed with modern DNA can work backwards to reconstruct a portion of the genome of a mammal that has been extinct for 75 million years (see “Ancient genes rise from the dead”). The aim in every case is similar: to understand what life was like in the past and to follow its path to the present.
Delving into our genetic past also promises the tangible benefit of new perspectives on genetic diseases. At least one of the genetic variants that cause cystic fibrosis in humans turns out to be…
