Science journalist Steve Olson, author of Mapping Human History : Genes, Race, and Our Common Origins. Also: Is California melting? Scientists report possible economic collapse in California due to global warning; Bush Administration has been fighting recognition of global warming, but now seems to be backtracking: Bush Administration scientists agree that human activity is driving global warming; Scientists create genetically engineered mice that are twice as strong and have twice the endurance of ordinary mice; Scientists announce they are beginning to unlock the secret of Burner Syndrome, the disease which causes pre-mature aging; Feds issue warning that hospitals must prepare for medical catastrophe if avian flu crosses over to humans.