The researchers, from the Guangzhou Institutes of Biomedicine and Health, edited 65 dog embryos, from which 27 puppies were born and only two had both copies of the gene disrupted. Even then, Hercules still produced some myostatin and was less muscled than Tiangou.
Beagles are commonly used in medical research in the USA and China. Lead researcher Dr Liangxue Lai told the MIT Technology Review, 'The goal of the research is to explore an approach to the generation of new disease dog models for biomedical research. Dogs are very close to humans in terms of metabolic, physiological, and anatomical characteristics.'
The researchers suggest that dogs could be engineered to mimic human diseases such as Parkinson's disease and muscular dystrophy, allowing potential treatments to be tested on them.
The myostatin gene, which inhibits muscle formation, can be deleted in nature, with examples including Belgian Blue cattle, 'bully whippets' and, rarely, humans including a child born in 2004. It is frequently cited in debates over hypothetical athletic 'gene-doping', and is being explored as target for gene therapy for Duchenne muscular dystrophy in the USA.
The results were published in the Journal of Molecular Cell Biology.