The behavior of 2.5 million nerve cells in parts of the brain important for vision, memory, reasoning and other tasks forms the basis of the new system, says Chris Eliasmith of the University of Waterloo in Canada, coauthor of the study, which appears in the Nov. 30 Science.???Most of the human genome???s harmful gene variants arose in the past 5,000 to 10,000 years.Can you imagine swimming in wat