Beagles named Hercules, at left, and Tiangou are the world’s first gene-edited dogs. =============================================================================================================================== Man’s best friend is now his newest genetic engineering project. Scientists in China say they are the first to use gene editing to produce customized dogs. They created a beagle with double the amount of muscle mass by deleting a gene called myostatin. The dogs have “more muscles and are expected to have stronger running ability, which is good for hunting, police (military) applications,” Liangxue Lai, a researcher with the Key Laboratory of Regenerative Biology at the Guangzhou Institutes of Biomedicine and Health, said in an...