La Jolla, CA – Brains are marvels of diversity: no two look the same – not even those of otherwise identical twins. Scientists at the Salk Institute for Biological Studies may have found one explanation for the puzzling variety in brain organization and function: mobile elements, pieces of DNA that can jump from one place in the genome to another, randomly changing the genetic information in single brain cells. If enough of these jumps occur, they could allow individual brains to develop in distinctly different ways.