Scientists Say Genetic Discovery Will 'Change Human Understanding'

Scientists have discovered a dramatic variation in the genetic make-up of humans that could lead to a fundamental reappraisal of what causes incurable diseases and could provide a greater understanding of mankind. The discovery has astonished scientists studying the human genome - the genetic recipe of man. Until now it was believed the variation between people was due largely to differences in the sequences of the individual "letters" of the genome. It now appears much of the variation is explained instead by people having multiple copies of some key genes that make up the human genome.