FIVE brothers and sisters who can only walk naturally on all fours are being hailed as a unique insight into human evolution, after being found in a remote corner of rural Turkey. Scientists believe that the family may provide invaluable information on how Man evolved from a four-legged hominid to develop the ability to walk on two feet more than three million years ago. A genetic abnormality, which may prevent the siblings, aged 18 to 34, from walking upright, has been identified. The discovery of the Kurdish family in southern Turkey last July has triggered a fierce debate. Two daughters...