Scientists create smart mice with added gene By Patricia Reaney LONDON, Sept 1 (Reuters) - Scientists in the United States said they had created a strain of smart mice by inserting a gene into the rodents' brains, proving it possible to improve the intelligence of mammals, including humans. The strain of genetically modified mice named Doogie were given extra copies of a gene called NR2B which helped them to learn faster and to improve their memory. ``They're learning things much better and remembering longer. They're smarter,'' said Joe Tsien, a neurobiologist at Princeton University. As they aged, the mice also ...