Muscled beagles

The first instance of the use of gene editing to produce modified dogs was just reported by Chinese scientists. Removing a gene called myostatin, the scientists created a beagle with double the muscle mass  of the average breed of the dog. Liangxue Lai, a researcher with the Key Laboratory of Regenerative Biology at the Guangzhou Institutes of Biomedicine and Health, said that the dogs have "more muscles and are expected to have stronger running ability, which is good for hunting, police (military) applications." The results of the project were reported last week by Lai and 28 of his colleagues in the Journal of Molecular Cell Biology. The scientists say they plan to create dogs with other DNA mutations, including those which mimic human diseases such as Parkinson’s and muscular dystrophy. “The goal of the research is to explore an approach to the generation of new disease dog models for biomedical research,” Lai added. “Dogs are very close to humans in terms of metabolic, physiological, and anatomical characteristics.” The Chinese beagle project was spearheaded by Lai and Gao Xiang, a specialist in genetic engineering of mice at Nanjing University. In both the U.S. and China, beagles are commonly used for biomedical research. Though Lai said they had no plans of breeding the muscular dogs as pets, other scientific teams, however, have pursued commercial goals for their gene-altered animal projects. In September, the Chinese institute BGI begun selling gene-altered, miniature pigs as novelty pets, for $1,600 each.


The newly developed genome editing technique, known as CRISPR-Cas9, refers to inexpensive but precise procedures that allow scientists to easily disable genes or rearrange their DNA letters. The effects of losing the myostatin gene are known in nature. One example of this DNA mutation is in the breed of ultra-beefy cattle called Belgian Blues that normally lack the gene and grow to hulking size. Retired scientist Eva Engvall says that among dogs, this mutation occurs naturally only in whippets (a medium-sized breed descended from the greyhound). In 2007, she helped identify the mutation affecting that breed. Engvall said she was impressed by the Chinese beagle project as it shows how gene editing might also be used to correct genetic illnesses that affect some dog breeds. “The point of this work was not to re-create myostatin knockouts,” Engvall says. “The point was to use the CRISPR technology in dogs. And in this project, the authors overcame some obstacles, in that dogs are a bit tricky when it comes to manipulating embryos.”

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